What Is Credit Card Verification Number?

What Is Credit Card Verification Number?

For your safety and security, we require that you enter your credit card's verification number - also known as the security code.
For Visa, Master Card, and Discover Card, this is a three-digit number printed on the back of your card. It appears after and to the right of your card number. For American Express, this is a four-digit number printed on the front of your card. It appears after and to the right of your card number.
Credit Card Security Code American Express Security Code