To process the refund of an order using the Checkout module, there are two methods:
Refund from the back office of your store
From your PrestaShop interface, navigate to the relevant order via Menu > Orders > Orders.
To process a full refund of the order, you simply need to change the status of the order to "Refunded." The entire order will be refunded, and you will find this refund in the list of your transactions for the order and in your activity tracking on www.paypal.com.
To process a partial refund, click on "Partial Refund" at the top of the order. You will be redirected to the bottom of the order page, where you will be able to enter how many products are affected by this refund, as well as the amount to be refunded for the products and for the shipping. You will also have the option to "Restock the products" in the case of a product returned in good condition. Click on "Partial Refund" at the bottom to confirm. The equivalent amount will be refunded, the status of the order is then "Partial Refund" and you will find this refund in the list of your transactions on the order and on your activity tracking at www.paypal.com.
Refund from the PayPal interface
From the Activity tab of your PayPal account after logging in at www.paypal.com, all completed payment transactions can be refunded using the "Refund" button to the right of the line. By clicking on it, you are redirected to a refund page, which summarizes the order amount and allows you to enter the total refund amount.
When you click on "Process a refund," if you have the necessary funds, the refund will be processed and your store will be notified. The status of the associated order in your back office is then changed to "Refunded" if you have refunded the entire amount, or to "Partial Refund" if you have only refunded a portion.