Kai's assistant's application for credit card is not standardized. Credit card refers to various media that record the relevant information of the cardholder's account, have the function of bank credit line and overdraft, and provide relevant banking services for the cardholder. It is an electronic payment card issued by commercial banks or other financial institutions with all or part of the functions of consumer payment, credit loan, transfer settlement, cash deposit and withdrawal, etc. No assistant can compare with the application security of official apps of various banks. Card assistants are not standardized in applying for credit cards, and there is a risk of information leakage.