This is the personal income tax you paid last year. The more you pay, the higher your monthly income will be. This should be consulted with the financial personnel of your unit, who withhold and pay taxes. Social security tap water and provident fund need to bring their ID cards to social security bureau or provident fund management center respectively, and ask them to issue corresponding payment certificates, indicating that they are used to apply for credit cards. Generally, credit card banks will issue income certificates, which can be issued by the financial department of the unit or the personnel and labor department, with official seals.