First log in to QQ, then click the mailbox icon on the QQ software to enter the QQ mailbox.
Click "Settings" on the QQ mailbox webpage.
Click "General".
Then find the personalized signature and click "Add Personalized Signature".
In the personalized signature setting window, fill in your signature and click "OK" after setting it up.
After completing the above operations, click "Save Changes" to realize the personalized signature of QQ mailbox.