Is there a bank transfer payment system?

Hi there - I'm not sure if I understood you correctly. Do you wish to accept payments via Bank Transfer? If so, then you can create a form with the purchase order. Basically, you'll only process the orders once you receive the bank transfer made by your customers.

Guide: How-to-create-payment-form-with-purchase-order

If you are, however, referring to something else, let us know and we'll be happy to help!