That's because your signature has not been revised successfully. Let's take a look at the detailed steps.

1. Open the mobile phone WeChat and click me.

2. On my page, click on the avatar.

3. In the personal information, click "More Information".

4. In more information, click Personalized Signature.

5. Then in the input box, delete the previous personalized signature, enter a new personalized signature, and click Save.

This changes the personalized signature of your mobile phone WeChat.