What is this?
The CVV Number ("Card Verification Value") on your credit card or debit card is a 3 digit number on VISA®, MasterCard® and Discover® branded credit and debit cards. On your American Express® branded credit or debit card it is a 4 digit numeric code.
Providing your CVV number to an online merchant proves that you actually have the physical credit or debit card - and helps to keep you safe while reducing fraud.