1, on the back of the credit card, in the upper right corner. There are seven numbers embedded in the card. The first four digits are the last four digits of your card number, and the last three digits are the security code.

2.CVV2 is the security code of credit card, which is the security code of credit card for online or telephone transactions. Generally, it is a 3-digit or 4-digit number printed on a credit card, and the printing position of different types of cards will be different. It is usually used to prove that the payer has a credit card at the time of transaction, thus preventing credit card fraud.