You can refund an entire order or part of an order from the Shopify POS Orders screen.
Refunded items are added to the inventory of your Shopify POS app's assigned location.
Refund an order
On the home screen of the Shopify POS app, tap ≡.
Tap Orders.
Tap the order of the item being returned.
Tap Return.
Use the + and - to enter the quantity of each item that you're refunding.
Tap Next.
Optional: If you don't want to return an item to your inventory, then tap Restock at this location, disable the restock option and tap Save.
Optional: Tap Refund shipping to refund the cost of shipping.
Optional: Enable Refund balance to gift card to issue a gift card to the customer for the refund amount. The gift card product needs to be published to the POS sales channel for this option to be available.
If the customer used more than one payment method, then you can split the refund between the same payment methods that they used. Tap Edit in the Amount to Refund section and enter the amount that you want to refund to each payment method.
Optional: Add a reason for the return.
When you're ready to process the refund, tap Refund.