Perhaps if we only use our Mac it is not necessary to resort to passwords to protect our documents ... or perhaps we can because we can lose our equipment and, when faced with certain documents, every measure is good.
Password protecting from Preview.
En App Store, and outside of it, there are applications that allow us to protect documents with a password, however, if what we want to protect is a PDF document, Preview It gives us that option if we need to resort to other apps. The process, as you are going to see, is really simple.
First of all, we open with Preview the PDF document to which we want to assign a password. Once open, we move to the menu Archive and there, pressing the key Option, we will see how the menu item Double It transforms in Save as…
select Save as and in the pop-up dialog box we check the box Encrypt from the bottom.
Next we enter the password that we want to assign to the PDF twice and we keep it in the place we want in our Mac.
Now, every time we want to open this document we will be asked for the assigned password.
SOURCE: CultOfMac