To issue a refund on eBay, you can follow these steps:

1. Locate the order in Seller Hub or My eBay Sold.
2. From the dropdown menu, select Send refund.
3. Choose a reason for the refund.
4. Specify a refund amount for the item or for the order.
5. Enter the desired refund amount and select Send refund.

As a seller, you can also issue a refund through a cancellation or return request, or a report that an item hasn't arrived. Additionally, eBay can issue a refund to your buyer as the result of an eBay Money Back Guarantee case or payment dispute.