How to make entry for items sold being returned by customer.

A warm welcome to the Community, trivaccainterior,

To record returned items in QuickBooks Online, you can create a refund receipt for this transaction. 

Here's how:

1. Click + New in the left panel and choose Refund receipt.
   
2. Select the Customer who returned the items.
3. Enter the Amount and the Product/Service.
4. Hit Save and close.
   

To know more about this process, check out this article: Record a customer refund in QuickBooks Online. This will provide you steps on how to link the refund to the customer's overpayment as well as reasons when to record a refund in QuickBooks.

I wish you continued success. Let me know if you have additional questions about this topic, I'll be your helping hand. Have a good one!