First, your ID has been registered for more than a certain period of time-three months.

Then, you can set up your own signature file by the following steps.

Go to your personal settings first and see if there are any signature documents.

If so, upload the picture you want to set to BD space album.

Copy address link (click on the picture, and "Copy image address" will appear. After copying, find the signature file settings and paste the copied address)

Go to the address bar of the signature file and wait for approval after confirmation.

As long as it's not too HX, it's usually a quick review, a few hours, but you should be mentally prepared.

You can set up five signature files.

I hope my answer can solve LL's problem.