You can leave feedback through your purchase history. 

If you haven’t already, you’ll see the option to leave feedback.

You can then:

• Select an overall feedback rating – positive, neutral, or negative
• Rate aspects of the transaction – including whether the item arrived on time, the accuracy of the item description, shipping costs, and the seller’s communication
• Write a comment about your experience
• You can also view all the feedback you’ve left or received in your Feedback profile. From there you can also follow up and respond to feedback.

Only registered eBay members can leave feedback. 

If you bought an item as a guest, you won’t be able to leave feedback about your experience.