In the payment masks it is possible to define whether a newly entered payment partner should be saved in the master data or not. This can be controlled per payment via the checkbox "Do not automatically save new payment partners" in the lower area "Other".
A general default setting for this check mark can be made in the system configuration under the "Payments" tab. The setting specified here is automatically applied when a new payment is created and can then be changed manually by the user in the payment mask if required.