Card verification codes
A Card Verification Code (CVC) is a number that provides extra security for credit and debit card transactions. When you buy something, you may be asked to enter in your card's CVC to prove that you have the card in your possession.
Where to find your CVC
The location of the CVC and number of digits varies by card type.American Express
The CVC is the four digits on the front of the card on the right-hand side.
The CVC is the three digits of the number on the back of your card in the signature bar.