For each purchase you make on the site, a receipt will be generated with the summary of the product purchased.
Receipts will always be available for viewing or downloading and storing in the Payments / Purchase Receipts section of your profile, until you decide to deactivate your profile.
To view payment receipts you will need:
Go to your Profile by clicking on your image;
Click on the Payments / Purchase Receipts section;
You will then see a page with your receipts.