A customer wants to add a gift message for their order. A trade buyer needs to enter their account reference number. A flower delivery customer needs to specify what time they want their order delivered. A furniture merchant needs to know which floor the delivery should go to.

Shopify's default checkout collects name, address, email, and payment details. That is it. If your fulfilment process or your customers require anything beyond that, you need to add it yourself.

The challenge: Shopify's checkout is one of the most protected parts of the platform. You cannot edit it freely. What is possible depends entirely on your plan, and the gap between standard Shopify and Shopify Plus is significant here. This guide explains every available option and which situations each one fits.

What does standard Shopify allow?

On all Shopify plans, there is one native mechanism for collecting extra information from customers: the order note.

The order note is a text box that appears on the cart page (not the checkout) and lets customers type any freeform information. It shows up in your order admin under "Customer note" and is accessible via the API. It is basic, but it works for simple use cases like gift messages or general delivery instructions.

To enable the order note in your cart, go to Online Store, Themes, Customise, navigate to your cart page, and look for a "Show order note" setting (most themes including Dawn have this as a toggle in the cart section settings).

The limitations are real: it is freeform text (no validation, no structured fields), it sits on the cart page rather than the checkout, many customers miss it, and there is no way to make it required or to conditionally show it based on products in the cart.

For merchants who need structured data, conditional fields, or checkout-level collection, you need an app or Shopify Plus.

Which apps solve this for non-Plus stores?

Several apps add custom field functionality on top of standard Shopify. The best-performing ones work by collecting the information before checkout (on the cart page or a pre-checkout popup) and passing it through to the order as attributes or in the order note field.

Checkout Comments by Effective Apps (free plan available, paid from £5 per month). Adds a simple comment/instruction field to the cart or checkout thank-you page. Good for basic gift messages or delivery notes. Straightforward to set up.

Order Delivery Date by Secomapp (from £7 per month). Adds a date picker and optional time slot selector to the cart or checkout. Used by food delivery, florists, subscription box, and click-and-collect merchants. Lets you block out unavailable dates and set cutoff times. The data appears on the order as an order attribute.

Hulk Form Builder by HulkApps (free plan, paid from £9 per month). A general form builder that can create product customisation forms, pre-checkout questionnaires, and cart-level fields. More flexible than single-purpose apps. Good for merchants who need several different field types (dropdowns, file uploads, checkboxes).

Infinite Options by ShopPad (from £9 per month). Focused on product options and line item properties rather than order-level fields. Useful for personalised products where you need engraving text, colour choices beyond variants, or custom specifications per line item.

A study by the Baymard Institute found that 29 percent of US online shoppers have abandoned a checkout because the process required creating an account or providing information they found excessive. Poorly placed or excessive custom fields can hurt conversion. Keep mandatory fields to an absolute minimum and only ask for what you genuinely need for fulfilment.

What does Shopify Plus unlock with Checkout Extensibility?

Shopify Plus merchants get access to Checkout Extensibility, Shopify's official framework for customising the checkout experience. This replaced the old checkout.liquid approach (which Shopify deprecated in August 2024) and is the only supported way to modify checkout on Plus.

Checkout UI Extensions are the key feature. These let developers build custom interface elements that appear inside the Shopify checkout itself, not before or after it. You can add:

Text input fields (for gift messages, special instructions, trade reference numbers)
Dropdowns (for delivery time slots, gift wrapping options)
Checkboxes (for consent to terms, marketing opt-in)
Informational banners
Custom line item summaries

These extensions appear natively within the Shopify checkout flow, which means they carry the same trust signals as the standard checkout. Customers see them at the information or delivery step rather than being redirected to a separate page.

Building a Checkout UI Extension requires a developer using Shopify's CLI and React. It is not a no-code tool. A simple custom field extension typically takes eight to twelve hours of developer time to build and deploy. Expect to pay £400 to £900 for a straightforward single-field addition, and more for conditional logic (for example, only showing a gift message field when a "gift wrapping" product is in the cart).

Shopify also offers Checkout Branding through Plus, which lets you customise checkout colours, fonts, and layout via the admin without code. This is worth doing regardless of whether you are adding custom fields.

How do you read custom field data in the order admin?

The data collected via order notes, order attributes, or line item properties all appears in different places in your order admin.

Order notes appear in the "Customer note" section of the order detail page. They are also available in Shopify's CSV order export.

Order attributes (the format apps like Order Delivery Date use) appear in the "Additional details" section on the order page, typically shown as key-value pairs (for example, "Delivery Date: 15 August 2026"). You can see these on the order and filter by them in some apps.

Line item properties appear on the specific line item in the order. If a customer ordered an engraved necklace and entered "Happy Birthday Sarah," you will see that text under the relevant product line in the order.

Checkout Extension fields on Plus are stored as order metafields and appear in the order admin under custom data, and are accessible via the API.

How do you pass custom field data to your fulfilment system?

Reading data manually is viable for low order volumes. For higher volumes, you need the data flowing automatically to whoever handles fulfilment.

3PL and OMS integrations: Most 3PL middleware tools (Mintsoft, Linnworks, Veeqo) can read Shopify order attributes and map them to their own fields. Check with your specific 3PL what order data formats they accept and configure your field collection accordingly.

Email notifications: Shopify's order confirmation and new order emails are templated using Liquid and can be edited to include order note and attribute data. Go to Settings, Notifications and edit the "New order" template to include {{ order.note }} and loop through {{ order.attributes }}.

Webhooks and API: For custom integrations, the Shopify order webhook payload includes all order attributes, notes, and line item properties. Your developer can read this data and pass it to any downstream system. See our guide on Shopify webhooks for more detail on this approach.

Zapier and Make: For simpler integrations, Zapier (from £19 per month) and Make (from £9 per month) can trigger workflows on new Shopify orders and extract specific order attribute values to send to Google Sheets, Airtable, a fulfilment email, or any connected app.

Key actions to take now

Enable the order note field in your cart if you have not already. Go to your theme editor, navigate to the cart page, and toggle on "Show order note." This costs nothing and covers basic gift messages and instructions immediately.
Audit what information you actually need at order level versus what you are currently asking for. Remove any non-essential fields to protect checkout conversion.
If you need a date picker, delivery time slots, or gift wrapping options, evaluate Order Delivery Date (from £7 per month) and Hulk Form Builder (free plan available) before spending development budget on a custom solution.
If you are on Shopify Plus and your checkout collects no custom data currently, get a developer quote for a Checkout UI Extension for your most pressing data need. A single focused extension is usually a contained, fixed-cost project.
Update your order notification email templates to surface order notes and attributes to your fulfilment team so the data does not get missed.
If you use a 3PL, check with them what custom field data they can receive and act on before investing in collection methods that your fulfilment flow cannot use.

Frequently Asked Questions

Can I add custom checkout fields on a standard Shopify plan without Plus?

Not inside the checkout itself. Standard Shopify does not allow checkout code modifications. Apps work around this by collecting data on the cart page or via a pre-checkout popup and passing it as order attributes. The customer experience is slightly different from a native checkout field, but for most use cases it works effectively.

Will custom checkout fields affect my checkout conversion rate?

They can, if not implemented carefully. Mandatory fields add friction. Optional fields are generally low-risk but should not clutter the checkout. The safest implementation is a clearly labelled optional field with a helpful placeholder (for example, "Add a gift message (optional)") placed at the end of the information step. Avoid adding fields in the middle of the address or payment sections.

How do I make a custom checkout field required on Shopify Plus?

Using Checkout UI Extensions on Plus, you can add client-side validation to any custom field to make it required before the customer can proceed. This requires developer implementation. You can also use Shopify Functions (another Plus feature) to validate order data server-side and block checkout completion if a required field is empty.

Can I pre-populate a custom checkout field based on the products in the cart?

On Shopify Plus, yes. Checkout UI Extensions can read cart contents and conditionally show or hide fields, pre-populate values, or change field labels based on what is in the cart. This is one of the stronger arguments for Plus for merchants with conditional data collection needs — for example, only showing a personalisation field when a customisable product is in the cart.

Shopify Custom Checkout Fields: How to Collect Extra Information at Checkout