Hi Aditya
When I meant configuration, it was more of the House Bank and Bank account creation, not Vendor or payment methods.
The table BNKA is for the bank master data. Table REGUH is filled when we run a proposal in transaction code F110. The bank selected for payment is dependent on Vendor as well as the ranking order defined in FBZP for the payment method.
I think additional details your functional should be able to give it to you.
Regards
Sowmya