Event participants who registered via paid tickets can get their receipts from the event page, as outlined in this article.
How to Get a Receipt
After logging in to the event page, select one's name at the top right corner and select [QR code and badge].
Select [Show receipt].
The receipt will be displayed in a new window. Users can print the receipt from this page if necessary.
To edit the information shown on a receipt, reference the following article: Receipt Settings