Skip to content

Shopify Horizon Theme Experts for Blocks and Migration

Horizon is Shopify’s own free theme and the foundation for its newest themes. It launched in May 2025 as part of a family of 10 new free themes, all built on theme blocks that can nest inside each other for more layout freedom than older section-based themes. Shopify Horizon theme experts turn that freedom into a store your team can still edit once Shopify ships the next update. The work merchants hire for: custom theme blocks, moves from Dawn or a paid theme onto Horizon, cleaning up AI-generated blocks, and customisation that goes beyond the 60 minutes of design time Shopify Theme Support gives each paid account. 33 experts carry the Horizon badge on shopexperts as of October 2026 (15 agencies, 18 freelancers). The US accounts for 6 of them, and Canada and the UK for 4 each. With that many to choose from, the brief does the filtering: name your current theme, the apps on your product pages and what you need to keep.

Top-rated Horizon theme experts

Erick Kagai
EK
Shopify ConsultantNairobi, KenyaFrom $285
4.93(73 reviews)
shopexpertsscore
85

I help online businesses make more money with what they already have. Your $100 in ads once brought back $1,000. Now the same $100, in ads or apps, quietly brings back less every month. You are busy running the business, so nobody chases why. So I start with an audit, the way a hospital starts with triage. A short call is the triage. A fixed-price read is the lab test. The results decide the fix, and the fix has a fixed price before it starts. Shopify speed and ad tracking fixes: for stores where the ads bring visitors but not sales. One example. A clothing brand's product pages took 15.4 seconds to load. Five weeks before Black Friday, I got them to 7.4 seconds. That is the job: I find what slows your store down, and I fix it. The same work keeps finding a second problem: numbers you cannot trust. The code that tells Meta or Google about a sale fires twice, so sales count double. Ads run across every product, with no check on which ones earn. Apps bill every month for work nobody has measured. So I also check what your money is really doing, instead of trusting what Google, Meta and the apps say. Then I fix what I find. I work with established stores run by their founders. To me, speed and ad spend are sales problems, not technical boxes to tick. What I work on, eight ways in: Speed check. I measure how fast your pages load for real shoppers on a phone. I find what makes them wait, and I fix it. Accessibility check. I test your store the way a keyboard user or a screen reader meets it. I check whether a widget sits on top of problems it does not fix. You get the findings in the order a complaint would reach them. Shopify deadline check. Shopify changes its rules on set dates. Scripts ended on 30 June. Order status script tags ended on 26 August. I find what has already stopped working on your store and what is dated ahead, and I make the repairs. Tracking and attribution fix. Meta Pixel, GA4 (Google Analytics) and server-side tracking. I remove the double counting and prove it in your own dashboards. Ad spend by product and the app bill get read in the same pass. Google and Meta recovery. Your products stopped showing on Google or Meta. I find where the connection broke and get them showing again. Sale price check. AI shopping tools, like ChatGPT, now get your "was" prices from Shopify. I check that yours reach them right. Builds and theme upgrades. New sections and modern themes, with your custom work and your tracking still running. Every change to the live site has a way back. Partner Seat. 25 hours a month. I watch speed, the pages customers see, broken links, tracking and app bills. Your work goes first in the queue. Each check is $285. If you go ahead, I take the fee off the fix price. Key results: Product page load time cut from 15.4 seconds to 7.4 seconds, 52% faster. Mobile PageSpeed on product pages from 18 to 28. The apps the client chose stayed in place, at their call. Two apps were billing to track what the store's own Google channel already did. I removed them, checked the tracking was clean, and took $199 a year off the app bill. Repeat clients going back to 2018. One store has come back for 14 projects over four years. How I work: A paid check first. It measures the real problem, no guessing. If you go ahead, I take the fee off the fix price. Work in stages. You approve each one. Every delivery ends with before and after numbers, and a short list of the next things I found. 80+ projects done. Clients in the US, Canada, UK, Australia and Denmark. Send me your store address. I will tell you what slows it down, whether your numbers add up, and what a complaint would find first. No commitment.

Theme & App Skills
Horizon Theme
Archetype Themes
Kickflip
Judge.me
Recharge
Love Loyalty Points & Rewards
Referral Candy & Affiliate
Shoplift – Split & A/B Testing
Visually – A/B Testing & CRO
Krown Themes
Out of the Sandbox Themes
Replo Landing Page Builder
Whiley Mai
Multi Vendor ‑ Puppet Vendors
Loop Subscriptions
Rivyo : Reviews & Loyalty App
ReConvert
Loop Returns
Attentive
GSC Email Marketing + Pop ups
GSC Countdown Timer Bar
Sparklayer
Rubik Variant Images & Swatch
eBay Integration ‑ DPL
Quotway
MultiVariants
Facebook & Instagram
Google & YouTube
Tapcart ‑ Mobile App Builder
FieldsRaven
Alpha: Loyalty Program, Points
Rabia Tariq
RT
Shopify Plus EngineerIslamabad, PakistanFrom $100
4.99(20 reviews)
shopexpertsscore
100

I’m a Shopify & Shopify Plus Engineer with 9+ years of hands-on experience, specializing in building, optimizing, and scaling high-performing eCommerce stores. At ShopExperts, I work with growth-focused brands to deliver clean, conversion-driven Shopify solutions, from custom theme development and advanced Liquid/JavaScript customization to store migrations, speed optimization, and complex third-party integrations. My core strengths include: Shopify & Shopify Plus development Custom theme development and heavy theme refactors Site speed optimization & Core Web Vitals Wix / Magento / Squarespace / Square Up / Kajabi / WordPress → Shopify migrations with SEO preservation Custom apps, APIs, and system integrations CRO-focused UX improvements for higher conversions I’m known for my structured approach, clean code, and transparent communication. I don’t just “implement features”, I focus on long-term store health, scalability, and performance, ensuring merchants are set up for sustainable growth. If you’re looking for a reliable senior Shopify engineer who understands both the technical and business side of eCommerce, I’d be happy to help. Big ideas, small questions, or “help, my store is broken” moments — let’s talk on a free discovery call 💬 https://calendly.com/rabia234t/call

Theme & App Skills
Horizon Theme
Shoplift – Split & A/B Testing
Rivo: Loyalty Program, Rewards
Instant Section & Page Builder
Mobile App Builder ‑ Appbrew
Klaviyo
Infinite Product Options
Judge.me
Kickflip
PageFly
Recharge
Shopify Checkout Blocks
Shopify Flow
Smile
Archetype Themes
Clean Canvas Themes
Eight Themes
Loop Subscriptions
Gempages
ReConvert
OneClickUpsell
ShipStation
Triple Whale
Stay ai
Zipchat AI Chatbot & Live Chat
ShipMagic
Attribuly
Kark: Multi Location Inventory
PushBundle
OrderRules
FieldsRaven
Woolman themes
Simple WordPress Blog Feed
Vela
Blox: Block Customer Blacklist
Kernvel AI Auctions
Alpha Sale

Let us match you with the right Shopify expert for your needs.

Share your project details, and we'll handpick the best matches from our Shopify expert directory.

Sumit Chakradhar
SC
Shopify Plus EngineerKathmandu, NepalFrom $100
4.97(130 reviews)
shopexpertsscore
100

10+ years, 500+ Shopify store owners, and countless successful projects—I'm a top-rated Shopify expert dedicated to helping brands improve their store's conversion, speed, functionality, and aesthetics. As the longest-serving developer at Shopexperts (formerly HeyCarson), I've built my reputation on meticulous attention to detail, reliability, and unwavering commitment to client success. My work speaks for itself —check out reviews from past clients who can attest to my dedication and results-driven approach.

Theme & App Skills
Horizon Theme
Archetype Themes
Clean Canvas Themes
Judge.me
Klaviyo
Infinite Product Options
Gameball: Loyalty Points Games
Eight Themes
Omnisend
PageFly
Recharge
Shop Pay Installments
Smile
FoxSell Bundle Builder
MESA
Dynamatic Cart & Upsell Engine
Candy Rack
Instant Section & Page Builder
Theme Updater & Backups | OOTS
Surge Themes
Gigit.ai
Rivyo : Reviews & Loyalty App
Troop themes
Fluorescent Design Inc.
Brickspace Lab
We Are Underground Themes
Kitenzo
Printify
Bold Upsell
Skio
Okendo
Getsitecontrol
GSC Email Marketing + Pop ups
Rubik Variant Images & Swatch
MultiVariants
Pixel Union
Alpha: Loyalty Program, Points
Lautaro Climent
LC
Front-End DeveloperBuenos Aires, ArgentinaFrom $65
4.91(58 reviews)
shopexpertsscore
100

I’m a seasoned web developer and Shopify specialist with over 5 years of experience delivering high-converting, beautifully designed online stores for clients worldwide. As a core member of the ShopExperts team, I’ve led and contributed to projects ranging from complete Shopify migrations to advanced customizations, always focusing on UX/UI best practices and modern e-commerce strategies. My approach blends technical excellence with creative vision: I believe that every brand deserves a digital presence as unique and inspiring as its mission. Whether you’re a startup seeking rapid growth or an established business looking to refresh your online store, I’ll help you unlock your site’s full potential. I specialize in all aspects of modern web development and optimization: From designing and building engaging websites, to customizing user experiences, integrating third-party tools, and ensuring your online presence performs at its best. My clients value my clarity, reliability, and my commitment to going the extra mile to achieve outstanding results. I’m passionate about staying ahead of e-commerce trends and turning challenges into growth opportunities. Let’s build the future of your brand, together.

Theme & App Skills
Horizon Theme
Klaviyo
Infinite Product Options
Judge.me
Omnisend
PageFly
Recharge
Shop Pay Installments
Shopify Checkout Blocks
Shopify Flow
Smile
Eight Themes
Archetype Themes
FoxSell Bundle Builder
MESA
Dynamatic Cart & Upsell Engine
Candy Rack
Love Loyalty Points & Rewards
Referral Candy & Affiliate
Rivo: Loyalty Program, Rewards
Replo Landing Page Builder
Arc: llms.txt
Surge Themes
Tapcart ‑ Mobile App Builder
Mobile App Builder ‑ Appbrew
Gigit.ai
Subi: Subscriptions & Loyalty
Truly Fine Pixels
We Are Underground Themes
Pixel Union
DSers
Bold Subscriptions
Bold Upsell
TikTok
Mechanic
Getsitecontrol
Rubik Variant Images & Swatch
ShipMagic
MultiVariants
FieldsRaven
Woolman themes
Simple WordPress Blog Feed
Vela
Kernvel AI Auctions
Alpha Sale
Laura Dolgy
LD
Shopify ConsultantOttawa, CanadaFrom $500
5.00(10 reviews)
shopexpertsscore
95

Shopify SEO and AEO Consultant–Let's get you found. I built my own Shopify store, The Kind Pet, to $50K in its first year organically with zero ad spend. That's the same structure I build for other stores: collections mapped to how people actually search, content that answers the question before they're asked, and a site that both Google and AI search engines can actually read. After 8+ years working in eCommerce (including building Shopify stores and helping brands double their traffic while growing organic revenue to 30–50% through SEO and conversion strategies), I made the move fully into Shopify growth consulting. What I work on: Site and navigation architecture by user intent Commercial keyword research paired with the collection build-out FAQ and AEO structure–mapped and marked up as schema Internal linking maps built for faster indexing Technical SEO and Core Web Vitals Backlinking SEO Content Marketing Conversion Rate Optimization Recent results: Skincare brand achieving $20K in Black Friday/Cyber Monday sales from organic sales Client organic revenue up 255% in one month, and a separate client up 104% in three months, following collection and keyword restructuring Repeat clients who return project after project once the structure is in place Types of clients: Small to medium-sized merchants Beauty, apparel, hardware, pets, etc. 2-6 year client lifetime–we strive for long-term partnerships Canadian merchants: I charge the same in USD and CAD, so you'll never have to pay for conversion.

Theme & App Skills
Horizon Theme
Klaviyo
Infinite Product Options
Judge.me
Omnisend
Shopify Checkout Blocks
Shopify Flow
Archetype Themes
Clean Canvas Themes
Eight Themes
Referral Candy & Affiliate
Rivo: Loyalty Program, Rewards
Visually – A/B Testing & CRO
Krown Themes
Out of the Sandbox Themes
Instant Section & Page Builder
Aftersell Post Purchase Upsell
Flits Loyalty Rewards Program
Reactiv ‑ Mobile App Builder
Macalytics SEO
Videowise
Loox ‑ Visual Product Reviews
Rivyo : Reviews & Loyalty App
Pandectes GDPR Compliance
Moon Bundles Upsell Cart AOV+
We Are Underground Themes
Kitenzo
Printful
Privy
OneClickUpsell
TikTok
Facebook & Instagram
Attentive
GSC Email Marketing + Pop ups
GSC Countdown Timer Bar
GSC Instagram Feed, Instafeed
GSC Product Labels & Badges
Stay ai
Sparklayer
Attribuly
Shopify Audiences
Shopify Bundles
Shopify Combined Listings
Shopify Forms
PushBundle
DiscountRay
Emil Gjorgjijev
EG
Ecommerce Operations ManagerSkopje, North MacedoniaFrom $65
5.00(14 reviews)
shopexpertsscore
95

A seasoned E-Commerce Specialist with a strong focus on Shopify and Klaviyo with over 6 years of experience.

Theme & App Skills
Horizon Theme
Klaviyo
Infinite Product Options
Judge.me
Omnisend
Smile
Shopify Flow
Shopify Checkout Blocks
Shop Pay Installments
Recharge
PageFly
Archetype Themes
Eight Themes
Referral Candy & Affiliate
Visually – A/B Testing & CRO
Krown Themes
OrderEditing.com
Recurpay
Fluorescent Design Inc.
AfterShip
Triple Whale
GSC Email Marketing + Pop ups
Stay ai
Sparklayer
Checkout Plus Customizations
Kaching Bundles & Upsells
Kno Commerce
Kark: Multi Location Inventory
Shopify Audiences
Shopify Forms
Vitals
Searchanise
Faire
DiscountRay
FieldsRaven
Simple WordPress Blog Feed
Alpha: Loyalty Program, Points
Ivan Seleznev
IS
Frontend EngineerBelgrade, SerbiaFrom $200
5.00(27 reviews)
shopexpertsscore
95

Senior Shopify Developer with 10+ years of experience building, customizing, and optimizing Shopify and Shopify Plus stores. I specialize in theme development, Liquid, JavaScript, HTML/CSS, performance optimization, app integrations, and creating scalable eCommerce solutions tailored to business goals. I’ve worked across the full development lifecycle, from translating design concepts into responsive, high-performing storefronts to troubleshooting complex technical issues and improving conversion-focused user experiences. I’m also known for fast delivery, clean implementation, and reliable collaboration to deliver business-driven solutions on time.

Theme & App Skills
Horizon Theme
Klaviyo
Judge.me
Archetype Themes
Eight Themes
Shoplift – Split & A/B Testing
Love Loyalty Points & Rewards
Krown Themes
Out of the Sandbox Themes
Whiley Mai
Slash Themes
ST
AgencyNew Delhi, IndiaFrom $500
5.00(16 reviews)
shopexpertsscore
80

At Slash Themes, we are a Shopify-focused commerce studio built to help ambitious brands launch, scale, and optimize high-performing storefronts with speed and precision. For over 7+ years, we’ve partnered with growing and enterprise merchants to architect Shopify and Shopify Plus experiences that are not only visually compelling but structurally built for scale. From complex replatforming projects to custom feature development, we create solutions that simplify operations, enhance customer journeys, and unlock new revenue opportunities. Our approach blends strategy, design, and deep technical expertise—covering custom theme development, custom app development, performance optimization, CRO, and data-driven enhancements. Every build is crafted with flexibility, speed, and long-term growth in mind, ensuring brands can evolve without limitations. More than a development team, we act as a dedicated Shopify partner—continuously refining, optimizing, and supporting the stores we build so our clients can focus on what matters most: growing their business. Core Shopify Services Shopify Store Setup & Configuration Shopify Theme Customization & Development Store Migration to Shopify (WooCommerce, Magento, etc.) Speed & Performance Optimization App Integration & Custom Functionality Bug Fixing & Troubleshooting Custom Design Implementation (Figma/PSD to Shopify) Ongoing Store Maintenance & Support ✦ With teams based in Germany and India, we support Shopify brands globally.

Theme & App Skills
Horizon Theme
Judge.me
Klaviyo
Recharge
Shopify Checkout Blocks
PageFly
Omnisend
Shopify Flow
Smile
Archetype Themes
Recurpay
ShipBob
Okendo
Triple Whale
Getsitecontrol
Checkout Plus Customizations
Michael Trang - Shopify & CRO Expert
MT
CRO SpecialistWashington, United StatesFrom $125
5.00(5 reviews)
shopexpertsscore
80

Logging in from Austin, TX, I'm a seasoned eCommerce and Conversion Rate Optimization(CRO) expert with over 20 years of experience in the online space, with 12 of those years in ecommerce, helping brands scale and maximize profitability. As the founder of MHT Media, I've led hundreds projects, leveraging data-driven strategies to optimize customer journeys generating real revenue. Here are some brands I've worked with. • Giantmouse (Shopify Plus) • Mad Viking Beard (Shopify Plus) • BlackMask Products (Shopify Plus) • ClaimSimple (WooCommerce) • Pastest (Shopify Plus) • Spaze (Shopify Plus) • And Arlen (Shopify)...and many others!

Theme & App Skills
Horizon Theme
Shoplift – Split & A/B Testing
Visually – A/B Testing & CRO
Klaviyo
Tapcart ‑ Mobile App Builder
Aftersell Post Purchase Upsell
Consentmo GDPR Compliance
Infinite Product Options
Judge.me
Loox ‑ Visual Product Reviews
Loop Subscriptions
Gorgias
Shop Pay Installments
Shopify Flow
Smile
Privy
Attentive
Bold Subscriptions
Bold Upsell
Loop Returns
Matrixify
Okendo
Pixel Union
Triple Whale
Wishlist Plus
Yotpo
Archetype Themes
Out of the Sandbox Themes
We Are Underground Themes
Eight Themes
Buy Button channel
Judge.me Email Marketing
Codeart
C
AgencySkopje, North MacedoniaFrom $5000
5.00(1 reviews)
shopexpertsscore
70

Codeart is a full-service design and development studio specializing in high-performing Shopify experiences for ambitious brands. With over 12 years of experience, our team blends strategy, creativity, and technical precision to craft fast, scalable, and conversion-focused online stores. We’ve partnered with global wellness, fashion, and consumer brands to design seamless eCommerce experiences that drive measurable growth. From UX strategy and CRO-driven redesigns to advanced Shopify integrations, every project is built around user insight and long-term performance. As a trusted Shopify Partner, we provide end-to-end solutions, from brand identity and UI/UX design to full development, optimization, and post-launch support, ensuring your store doesn’t just look good, but sells better. Industries Served: Health & wellness, fashion & apparel, consumer packaged goods, and lifestyle brands.

Theme & App Skills
Horizon Theme
Klaviyo
Judge.me
Omnisend
Infinite Product Options
Recharge
Shopify Checkout Blocks
Shopify Flow
Smile
Eight Themes
Archetype Themes
Checkout | Flow
Multi Vendor ‑ Puppet Vendors
Kim
Loop Subscriptions
Shopify Audiences
Shopify Bundles
Shopify Combined Listings
Shopify Forms
Shopify Fulfillment Network
Blox: Block Customer Blacklist

What a Horizon theme developer builds

Custom theme blocks. Horizon is built on theme blocks, the latest theme architecture, and those blocks can nest inside other blocks. A developer builds the store-specific pieces Horizon doesn’t ship with, as blocks your team can add, reorder and nest in the editor without breaking the page.

Moving onto Horizon. Switching from Dawn or a paid theme isn’t an in-place update. Shopify’s guidance is to add the new theme, customise it, and only then replace your current one. The developer rebuilds content, settings and any custom code on Horizon while the old theme stays live.

Hardening AI-generated blocks. Sidekick can generate a theme block from a plain description. Shopify wraps those blocks in a special _blocks.liquid section that isn’t a standard theme section and can’t be rendered manually. An expert reviews what your team generated, rebuilds the keepers as proper theme blocks and clears out the rest.

Configuring what’s already there. Horizon ships with a slide-out cart, quick buy, in-store pickup, enhanced search, a mega menu, swatch filters, back-in-stock alerts, lookbooks and size charts. A lot of good Horizon work is setting these up properly before anyone writes code, and switching off apps that now do the same job twice.

Keeping a customised copy current. Shopify keeps shipping Horizon releases, and a customised copy won’t take them cleanly on its own. An expert merges each release into your version and retests the pages you changed, so you don’t fall further behind with every update.

Plus features. Horizon supports Combined Listings, which needs a Plus or enterprise plan. On those stores, experts set up the theme side so grouped products display properly.

How much does a Shopify Horizon theme expert cost?

Horizon is free, so every dollar goes on the work. The tiles use the starting prices on all 33 Horizon-badge profiles, in USD as checked in October 2026, minus any profile priced at zero. Each one is the minimum an expert lists for any project, not an estimate for your store.

Middle half

$100 – $500

Where half of Horizon profiles start

Median

$200

The midpoint across 33 Horizon experts

Top quarter

$500 – $5,000

The highest starting prices in this group

The spread is wide because the work is. Arranging built-in blocks on a new store is a small job. Rebuilding a customised store from Dawn onto Horizon is a project. The biggest drivers are how much custom code your current theme carries, how many apps touch the product page and cart, and whether you want custom blocks your team will edit.

Try Shopify Theme Support first for small changes, since each paid account gets 60 minutes of design time. For a quote, send your current theme and version, your installed apps and screenshots of anything custom you need to keep. The theme customisation cost guide covers typical scopes.

Before you build on the Horizon theme

Horizon, or the Horizon family? “Horizon” can mean the single free theme or the family of 10 themes that share its foundation, which includes Ritual, Fabric, Tinker, Dwell, Pitch, Vessel, Heritage, Savor and Atelier. All are built on theme blocks. When you brief an expert, name the exact theme you’re on.

AI blocks are no longer a reason to choose it. Sidekick’s AI block generation launched with Horizon, but since 10 December 2025 it works with every Theme Store theme. Pick Horizon for its architecture and built-in features, not for AI generation.

Releases come quickly. Horizon went from launch to version 4.x in about 16 months, and 4.2.0 arrived on 18 September 2026 with a cart drawer fix. Each release brings fixes, and each customised file turns that release into a merge. A good expert keeps custom work in separate blocks so updates stay small.

Some edits are already done for you. The inventory block, badge positioning and language and country selectors are built into Horizon-family themes. If someone quotes to add them by hand, ask why.

Plan limits. Horizon is free on every plan. Combined Listings, which the theme supports, only works on Plus and enterprise plans, so check your plan before paying for that part of a build.

Translations. EU translations come with the theme, and the latest release improved support for right-to-left languages. If you sell in several languages, ask for every one to be tested on product, cart and search pages before launch.

Horizon projects on expert profiles

Development is listed by 25 of the 33 badge holders, and so is store setup. On Horizon, the categories translate into these projects:

Theme block development

25 list development: custom and nested blocks your team can edit

New store builds

25 list store setup: presets, built-in features and launch checks

Marketing and growth

12 list it: lookbooks, landing sections and merchandising

Design and UX

11 list it: layout, typography and mega menu structure

Consulting and strategy

10 list it: whether and when to move onto Horizon

AI and emerging tech

6 list it: reviewing and rebuilding Sidekick-generated blocks

Horizon theme questions from merchants

How do I customise the Shopify Horizon theme myself?

Start in the theme editor. Horizon is built on theme blocks, so most layout changes mean adding, nesting and reordering blocks rather than editing code. Sidekick can generate a custom block from a plain description, and Shopify Theme Support gives each paid account 60 minutes of design time. Hire a developer when you need blocks your team will reuse, or code you’ll have to maintain through updates.

Can I set up a Horizon theme mega menu without code?

Yes. A mega menu is one of Horizon’s built-in features, alongside enhanced search, swatch filters and colour swatches. The real work is the structure: which collections go where, how many levels, and which images help shoppers choose. A developer only comes in if you want a layout the built-in menu doesn’t offer.

Is the Horizon theme Shopify’s main theme now?

Shopify calls Horizon its new design foundation. It launched in May 2025 with a family of 10 new free themes built on theme blocks, and it keeps getting updates: version 4.2.0 shipped on 18 September 2026. Theme blocks are Shopify’s latest theme architecture, and the whole Horizon family is built on them.

Can I move from Dawn to Horizon automatically?

No. Shopify’s guidance is to add the new theme from the Theme Store, customise it, then replace your current theme. Content and settings need redoing, and any custom code from Dawn has to be rebuilt as Horizon blocks. Ask any expert for a written list of what they’ll rebuild before you agree the scope.

Are AI-generated blocks safe to keep?

For simple content, often yes. Sidekick wraps generated blocks in a special _blocks.liquid section that isn’t a standard theme section and can’t be rendered manually, which limits how you reuse them. For anything structural, such as the product page layout, cart or navigation, have a developer rebuild it as a standard theme block.

Do I need Shopify Plus to use Horizon?

No. Horizon is free on every plan. The one exception is Combined Listings: Horizon supports it, but the Combined Listings app only works on Plus and enterprise plans. The rest of the feature list, from the slide-out cart and quick buy to back-in-stock alerts, comes with the theme.