“Card Verification Value” is an anti-fraud feature to help ensure that the person placing an order is in possession of the credit card.
The CVV is a three or four digit number printed on the front or back of the credit card.
The CVV appears in different places on different types of cards:
American Express: Four digit number printed on the front of the card, above the end of the embossed account number.
MasterCard / Visa / Discover / Diners Club / JCB: The final three digits printed on the signature panel on the back of the card, following the account number.