Go to the Gap card-member account services website (see Resources).
Click "Register" under "New Users."
Enter your Gap card number, the last four digits of your Social Security number, your e-mail address and your date of birth. This will validate your online account.
Select a security question and answer, and select a security image. You will be asked for these later to access your account, so don't forget them.
Click "Pay Your Bill," then click "Add a Bank." Enter the name of your bank, your account number and your bank's routing number.
Choose how much you want to pay. The payment you make will be processed within 72 hours.