Take the operation of Android phone as an example.

First open the personal income tax app and click on the personal center at the bottom of the home page.

Click login in the personal center interface.

Enter the personal income tax app account number and password, and click Login.

Return to the Personal Center and click the Security Center tab to enter.

Enter the security center, click modify mobile phone number to enter,

Enter the modification interface, click and select the modification method.

Enter the old mobile phone number for verification, and click Next. That's good.