iReceivables - Enter customer bank / Credit Card details without any open invoice

This is a question on Standard functionality / behavior.
In iReceivables, if we have to enter any Bank Account Details, then the relevant page to enter bank details opens when we click on the ‘Pay’ Button on the Account tab or if we click on the ‘Pay’ button on the individual transaction.  This Pay button on the Account tab is visible only if there are any open transactions. In other words, customer can enter Bank Details only if there are any open transactions.

The question here is – How can we enter Bank details in iReceivables for a customer which does not have any open transactions ? As per our business process, only when customer enter their bank or credit card details in iReceivables, we create the Invoice.