Erase signatures from the Mac OS Catalina V10.15 Preview app forever I've been using the Preview App to generate my passwords and to be able to sign virtually. But now what I want to do is to erase them completely, so that nobody can access them.
For example, if I sell my Mac in a hurry, or if someone accesses my Mac, I want to make it impossible to access those signatures.
I don't mean to press the X (cross) that appears after generating the signature; because I think that by pressing that, that signature must be saved somewhere. I don't know. What I'm saying is to eliminate it in a more strict way, forever.

Is it possible to do this? How?
Signatures are stored in a property list file at the following path:
~/Library/Containers/com.apple.Preview/Data/Library/Preferences/com.apple.Preview.signatures.plist

You can remove this file and empty your trash to be sure they're gone. Any security/assurance you need beyond this will require advanced techniques or a complete wipe of your hard drive.