I want to know how to automatically "signature is valid".

By adding it to a certificate that users can trust directly
"There is a problem with one or more signatures" -> "Signatures are valid" You can act.

I would like to know how to say "signature is valid" without registering additionally to a direct trusted certificate.
The DocuSign PDF says, "Your signature is valid," even if you don't register yourself.

Please check the image.