Defining Business Partner Banks 
You define your business partners' bank details in the customer or vendor master record by entering the bank country, the bank key (this may be the bank number) and the bank account number for each of your business partners' bank accounts. This information can then be used for automatic payment programs. The payment program uses these details to determine the bank address and bank account number for credit transfer forms.
There is no limit to the number of bank details you can enter. The business partner's bank is linked to the bank master data via the bank country and the bank key (country-specific bank identification).
