This is probably because I accidentally deleted my signature when I was operating WeChat. It doesn't matter, just reset it without affecting normal use. The operation method is as follows.

1. Open WeChat, log in with your own account and password, jump to the "I" page in the lower right corner, and click the avatar in the upper left corner.

2. Click the "More" option in the new personal information interface, find the "Personalized Signature" and open it.

3. You can edit your favorite personality signature in the column of personality signature, with both words and expressions. If you want to add pictures, you can only add expressions under the emoticon column below, and others are not allowed. Click "Save" after editing.