You cannot prevent someone from emailing a file, but you can prevent people from opening a PDF. You can encrypt a PDF using a person's digital ID (public key) so that only they can open it. The person would have to set up a digital ID and send it to you, and you could then set up the document security to use it.
Another option is to set up the documents security so that a password is required to open it, but the password could be easily given out along with the document.
Another option is to set up the documents security so that a password is required to open it, but the password could be easily given out along with the document.
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