There is usually a seven-digit number behind the signature column on the back of a credit card. The first four digits are the last four digits of the card number, and the last three digits are the security verification code of the card, that is, "CVV code", which is generated by the issuing bank through coding rules and encryption algorithm for security management.

Directly printed on the card, customers can find it directly by flipping the card.

The credit card signature field is located on the back of the credit card. There is a blank space on the back of the credit card.