The cvv on the visa card refers to the credit card security code, which is the security code for online or telephone transactions of credit cards. This is very important.

Cvv on visa card is a 3-digit or 4-digit number generated by card number, expiration date and service constraint code, which is basically in the card magnetic stripe and 2-track user-defined data area.

In order to better prevent the leakage of the security code, relevant users can cut a small piece of tape and stick the cvv code on the visa card to prevent leakage.