[jstx1]

Word documents are most often required by 3rd party recruiters who want a convenient way to edit your CV before sharing it with an employer. It's not that common but it happens. That's why it's best to use pdf instead. If they insist on a word document, you can just refuse to work with them.

[Beltalowda]

In my experience a lot of time what they want is to redact personal information so they can send your CV to employers without the employers trying to "e-stalk" you and hire you outside of the recruiter (and thus not pay the recruiting fee). I actually got hired like this once (although I didn't know it at the time; the owner mentioned a year after I worked there).

I write my CV in HTML, as that's just the easiest way to get my CV to look exactly how I want it, and then "print" it to a PDF in Firefox. I also have a little JavaScript to redact personal information if I add "#redact" to the URL, and send a PDF of that too to recruiters after I noticed that a recruiter had completely massacred my pixel-perfect CV that I obsessed over by copy/pasting it in some ugly crooked layout and sent that horrible thing to companies :-/

All of that said, I haven't used recruiters for many years, but back then my "redacted" PDF solved the issues for me.

[anitil]

They'll also strip your contact details so that the company can't reach out to you directly.

Any recruiter who trusts their clients so little is probably not worth your time, however

[derekp7]

Pasting a picture of each page from a PDF in the Word doc works too, to keep them from editing it. Not sure if there is a way to hide the keywords in it (paste it in white/on/white text, 1-pt font, and have the picture overlay the text?)

[jstx1]

Picture in a word doc sounds like the worst of everything - looks unprofessional to a human and it doesn't work with automated CV parsers.