Quick answer
If the discount code box is missing at checkout, do not start by editing the theme. First check whether the store has an active discount, whether the checkout came from a draft order, whether the customer is using Shop Pay, and whether the field is hidden inside the mobile order summary.
Symptom
Customers reach checkout but do not see a place to enter a discount code. Sometimes they only see a gift card field. Sometimes the field exists on desktop but seems missing on mobile.
Most likely causes
- No active discount code exists. Shopify’s discount FAQ says the field might not appear if there is no active discount code available.
- The checkout came from a draft order invoice or link. Shopify says customers cannot apply discount codes themselves by default from draft order checkouts.
- Shop Pay state. Shopify notes that customers using Shop Pay may need to log in before the discount field displays.
- Mobile order summary is collapsed. On mobile, Shopify hides the order summary and discount field behind the “Show order summary” toggle.
- An app changed checkout behavior. Product options, wholesale, B2B, or draft-order apps can change the path into checkout.
Quick checks
- Go to Discounts and confirm at least one discount code is active and usable.
- Test a normal storefront checkout, not a draft order invoice link.
- Test desktop and mobile separately.
- On mobile checkout, tap Show order summary and look for the field there.
- Test in a browser where Shop Pay is not already taking over the flow.
Theme, app, or code checks
- Do not look in theme files first. The standard Shopify checkout discount field is not controlled by normal theme code.
- Check whether a product-options, wholesale, B2B, quote, or preorder app is creating draft orders.
- Temporarily test without the app path if possible: add a simple product to cart and checkout normally.
- If the field appears on a normal checkout but not in the app-created checkout, the app workflow is the likely cause.
When to stop guessing
Contact Shopify Support if the field is missing on a normal checkout with an active discount and no app/draft-order path. Contact the app developer if the missing field only happens when a specific app or draft-order workflow is involved.
Prevention checklist
- Document which checkout paths are standard checkout and which ones are draft-order or app-generated.
- Test every new discount on desktop and mobile.
- Add customer-facing instructions if mobile shoppers need to expand the order summary.
- Avoid running discount campaigns before confirming the field is visible in the actual checkout path customers use.