Transmitting the transaction receipt to the buyer
When iframe mode is enabled, the buyer can't view the transaction receipt on the summary page.
The receipt will automatically be sent by mail (provided that the notification rule "Confirmation e-mail of payment sent to the buyer" is enabled on your Merchant Back Office).
The buyer's e-mail is essential when using iframe mode.
Use the vads_cust_email field in your payment form to transmit the buyer's email address.