If you search for "How to issue a returns label" at "Help & Contact", top of page, it says:
"When you accept a return from your returns dashboard, you have the option to Upload your own label. If you have a preferred postal carrier, you can use this option to provide your own return postage label to the buyer. Uploading your own return postage label automatically sends the buyer a return label, which they can download from their Return details page. This method also captures the tracking details so you, the buyer, and eBay can all track the item.
If you’ve set your return rules to approve return requests automatically, you won’t be able to upload your own return postage label. With automated returns, eBay immediately sends your buyer an eBay return postage label to speed up the return."
