The credit card verification code is the three digits after the signature column on the back of the card, also called the security code. In English, it is CVC2. The card verification code is like the ID card of a credit card. When spending on overseas websites, you only need to use the card verification code to complete the transaction. If your credit card doesn't have an authentication code, you can-you can call CITIC's credit card customer service hotline to ask for it. The card can't be activated without the check code, which is the security code of the credit card, and it can't be done without it at a critical moment. Ask the customer service what's going on There may be a reason why manufacturers forget to print this kind of thing. Don't panic when things happen. Don't use it in a hurry. If the customer service does not solve it, you can go offline to solve it.