Have looked this up on help pages but all it says is ...
"You can also send an invoice from the item listing in the Sold section of My eBay."
When I looked there I couldn't see anything about printing an invoice, when i ticked the sold item the options that are available are :
Delete, Print Postage Labels, Relist, Add Note, Add to List, Tracking Number.
I tried 'Add Note' in the hope that it was the one but that just added a note to that item on the sold page.
Can anyone help?

