In macOS, there’s a built-in feature that allows you to add a password or encrypt a PDF using the apps that came with the Mac called Preview. It is also a default viewer for images and PDF.

You would need to add a password or encrypt it to ensure the PDF that you would share contains private information that can only be opened by the person you intended to allow viewing. Once encrypted, you may share the document via social messaging like WhatsApp or email them.

Watch the step by step video below.