When your customers receive the email invoice and click on the Pay Now button, they are sent to a secure website page to make a payment using a credit card. If your customers create a Web Pay account, they will have access to a list of their open and overdue invoices for payment. However, if your customer prefers to pay an invoice without creating an account you must select Send Invoices with Web Pay option for this customer and I Use Direct Web Pay in the Payment Details tab of their customer card.