1. First, turn on the phone. We found the information icon on the desktop of the mobile phone. Click the icon to enter the information page.

2. After entering the information page, we found that there are three small buttons in the upper right corner of the page. Click the button to enter the next step.

3. Then a window will appear on the interface. We will find the "Settings" option in the window, and click this option to enter the settings page.

4. After jumping to the settings page, we find the "More Settings" option on the page and click it to enter the more settings page.

5. Next, in more settings pages, we find that there is an option of "personalized signature" on the page, and there is a toggle button behind this option. Click it to open it.

6. Then you can see the option of "signature content" on the page. When we click this option, a signed content window will appear on the interface.

7. Finally, in the signature content window, after we enter the signature content in the text box, we just need to click the "OK" button at the bottom of the window.