How to make a part of a Pdf document unreadable?

Question

PDF

Good day. Please tell me how to create a document, most of which will be read only on my computer, and on others part of the text, scribbles, etc.
I tried to download Google fonts and other Cyrillic fonts, installed them in Worde, but after saving they are displayed well on another computer.
Unchecked the Word "Convert text to bitmap if fonts cannot be embedded" checkbox when saving to Pdf .
It's just that when you change the encoding of the entire document, all the text breaks and is not converted back.
Maybe it's better to collect the document not in Word?