I would like to certify a document to prevent tampering & protection. I don't use Password since it can be removed. Is there a way to certify a document without signing it?
Try the certificate security.
File > Properties > Security
Which Option do I choose from there?
Do I select - Validate All Signatures, Certify (Visible Signature), or Certify (Invisible Signature)?
Where does you see this?
Certifying a PDF is applying a specific kind of signature. Thus, no, you cannot certify without signing.
Is there a way to certify a document without signing it?
Other mechanisms also can be removed
I don't use Password since it can be removed.
Not certificates. That's very difficult to remove