Every Plus merchant eventually asks the same question: how much of this checkout can we actually change? The honest answer sits between the two stories they hear. It is not the locked box of old, and it is not the blank canvas some agencies imply.
Modern Plus checkout is built from governed parts. Understanding which parts are yours to move, which accept new functions, and which are fixed for security and upgrade reasons saves months of planning features that were never possible.
What the editor lets you change
Branding is fully yours: logo, colors, fonts, corner styling, and the visual treatment of the checkout and order status pages, all managed in the editor without code. For most stores this covers the largest visible gap between checkout and the rest of the site.
Layout changes are modest by design. Sections can be adjusted and some elements reordered or hidden within limits, but the core structure of information, shipping, and payment steps stays where shoppers expect it.
Extensions: new abilities in set places
Checkout extensions add functions at defined points: a delivery date picker, a loyalty message, an upsell, a custom field, a trust block. If the job fits a slot, an extension, bought or built, is the supported way to add it.
The slot system is the trade. You gain upgrades that do not break and a checkout that stays compatible, and you give up placing anything anywhere. Most real requirements fit the slots. The ones that do not usually turn out to be habits from older platforms.
Functions: changing the rules
Functions are where Plus customization gets powerful. They can rename, reorder, or hide payment and delivery options, apply discounts with custom logic, and validate cart or checkout data against rules you define.
This is logic, not layout, and it changes what the checkout does rather than how it looks. A store that needs certain shipping methods hidden for certain products, or discounts that standard rules cannot express, is exactly the store functions were built for.
What remains off limits
You cannot add arbitrary scripts to checkout, restyle it with free form CSS, or move payment capture outside the approved methods. Shop Pay and accelerated options follow their own rules, and some steps stay standardized so shoppers can trust any Plus checkout.
Plan with the map, not against it. The stores that get the most from Plus treat the constraints as a design brief: brand thoroughly, extend where the slots allow, and put custom effort into functions that change revenue, not pixels.
Related reading
These earlier guides go deeper on connected questions: The Discount Code Field: A Small Box That Sends Shoppers Away to Search, Address Autocomplete at Checkout: Faster Forms, New Kinds of Errors, and A Checkout Extension Upgrade Checklist Before the Deadline Forces You.
Frequently asked questions
Can I redesign Shopify Plus checkout completely?
No. You can brand it fully and extend it in defined places, but the core layout and payment steps stay standardized. That control is deliberate: it keeps checkouts fast, secure, and familiar to shoppers across Plus stores.
What is the difference between extensions and functions?
Extensions add visible features in set positions, such as a date picker or a message block. Functions change behavior behind the scenes, such as which delivery options appear or how a discount is calculated. Many projects use both.
Do I need a developer for Plus checkout customization?
Branding and many app based extensions need no developer. Custom extensions and functions do, because they are real code deployed to your store. The middle path, installing a reputable app that provides the extension, suits most stores.
Will my customizations break when Shopify updates checkout?
Supported customizations are built to survive updates, which is the main reason for the slot system. Stores using approved extensions and functions generally upgrade without checkout work, unlike old checkout.liquid modifications which required constant care.