Use Customer Reports
Easily see which customers have turned on auto pay and have signed up for the customer portal.
To view Customer Reports, navigate to Reports > Customer Reports.

Customer Portal Registrations Report
This is the list of customers that are registered for your Customer Portal. By clicking on the section header, you can collapse this section to more easily view the Auto-pay section below.

Use the search box to search by a customer’s name, display name, or email. Click the up/down arrows on the right of each column header to sort the selection.
In the Email Confirmed column, you can see the confirmation status for each customer. Remember, your customers need to confirm their email addresses before they’ll be able to use the Customer Portal.
Auto Pay Enabled Report
This is the list of your customers who have auto-pay turned on.

See the auto payable Invoices column to view the number of open, auto-payable invoices. If a customer has multiple auto-payable invoices, you will be able to view the total dollar amount of these invoices.
Search for a specific customer by name or display name.
At a glance, check the Payment Method column to view which stored payment method the customer has on auto pay.