The Payments Preferences screen can be accessed from your dashboard by clicking on the vertical ellipsis [] on your Payments App and selecting Preferences.
The preferences menu allows you to choose the email templates sent out from the Payments App.
Email Outgoing Activity Type: When an email is sent to the customer via the Email button, an activity is created. The activity type is set to this dropdown.
Email Notification Template: Email template used when clicking the Email button on the payment, which sends an email to the customer (unless the contact is flagged to opt out of billing emails).
Internal Email Notification Template: Email template used for the notification email sent to the Method User assigned to the payment.
Note: You can create custom email templates using Method's Email Templates App.