Was the item actually sold as a collection item?
If it wasn't sold as a collection item, and you just chose to collect it instead of having it delivered, then you won't be able to confirm receipt other than by leaving feedback.
If it was a sold as a collection item then, as already advised, you would have received a collection code in your order details and confirmation email which you need to give to the seller. You can also mark it as collected in your order details.
How to arrange a local collection
After completing your purchase, you’ll receive an order confirmation email with a collection code (a QR code and 6 digit code) to show the seller when you meet. You can also access your collection code on the order details or via Contact Seller on the eBay app.
The seller will scan or enter the code to confirm collection and ensure a safe and protected transaction.
Once you’ve collected the item, you can also confirm this directly in the order details.
