Help Desk x Close Window    Credit Card Identification Number A credit card Identification Number is an added safeguard for your credit card purchases. Depending on the type of credit card you use, it is the 3- or 4-digit number printed on the back or front of your credit card. For most online credit card purchases from us, the Identification Number is required information. American Express Your identification number is the 4-digit number found on the far right on the front of your credit card Visa Your identification number is the 3-digit number found on the back of your credit card near the signature panel. MasterCard Your identification number is the 3-digit number found on the back of your credit card near the signature panel. If your credit card does not show an Identification Number, you are not required to enter one.