The CVV number (or Card Verification Value) is needed to make a
purchase online. It is the last 3-digit number found on the back of
credit and debit cards that bear the VISA® or MasterCard® logos.
Providing your CVV number proves that you actually have the physical
credit or debit card in your possession when paying online. This also
helps to keep your card information safe while reducing fraud.
NOTE:
CVV numbers are NOT your card's secret PIN (Personal Identification
Number). You should never enter your PIN number when asked to provide
your CVV. PIN numbers allow you to use your credit or debit card at an
ATM or when making an in-person purchase with your debit card or a cash
advance with any credit card.