Could you please be a little more specific about what margins you would like to change, printer, page width, pull downs, there are to many margins to take a guess here as each would have a different answer.

So please expand on the issue and also what version of Firefox please as it is not showing up here.

I neet so set/control margins from Page setup/Margins & Header via GPO or script. Firefox version is 53.02

Please upgrade to version 54

https://support.mozilla.org/en-US/kb/update-firefox-latest-version

So it is printing you are talking about is that correct ?

We use version 53.02 for specific application and upgrade is not possible.