The credit card security code is printed on the back of the card to the right of the signature. Credit card security code is a security code used by credit cards when conducting online or telephone transactions. It is usually a 3 or 4-digit number printed on the credit card, and the location of the printing will vary on different types of cards. It is often used to prevent credit card fraud by verifying that the payer owned the credit card at the time of the transaction. The security code of the VISA card is called CVV2 (Card Verification Value 2), which is a 3-digit number and is printed flat on the signature line on the back of the credit card at the last 4 digits of the card number. The credit card security code is equivalent to the credit card's ID card. We can use this code to conduct consumer transactions. Shopping on overseas websites does not require a password. As long as the buyer provides an account number and security code, the transaction can be completed. In China, there are also merchants that have signed contracts with banks to complete phone transfers without a credit card password and only with a security code. Therefore, everyone must take good care of their credit cards and keep them out of their sight when making purchases to avoid others remembering your credit card account number and security code.