Your Cards Security Code:

American Express
Look for the 4-digit code printed on the front of your card just above and to the right of your main credit card number. This 4-digit code is the credit card Security Code.

MasterCard
Flip your card over and look at the signature box. You should see a 16-digit credit card number followed by a special 3-digit code. This 3-digit code is the credit card Security Code.

Visa
Flip your card over and look at the signature box. You should see a 16-digit credit card number followed by a special 3-digit code. This 3-digit code is the credit card Security Code.