Most Credit Cards
On most credit cards, with the notable exception of the American Express card,
the credit card verification number can be found on the reverse side of the
card. The number is an extra three digits printed inside the signature area
after the credit card number. This number is not embossed into the front of
the card - it only appears on the back.
On the American Express card, the number is four digits and appears just to
the right of the embossed credit card number on the front side. It is not
raised, like the credit card number, it is simply printed onto the front. See
the picture for an example.