How will my customer get their receipt?

Hi,

If you are referring to a payment form, you can send your user a customize invoice/receipt using Autoresponder email. Autoresponder email are emails that are sent to the user that fills up the form automatically upon submit of the form. To know more about Autoresponder email, you can check this article for more information: Creating a Form Autoresponder.

Do let us know if you need further assistance.

Regards.