I'm learning too but I don't think it's on it's own, except to be "mach" like mach ten speed or a mach Gillette razor.
(Not a native speaker) from what i gather the extra מ means from, so just writing מך would not be grammatically correct/ convey the same meaning
You don't need it here but I'm sure it does. Both my laptop, Mac. And my mobile phone & tablet (android, different versions) have nikudot). There's a list of options on the Duolingo web discussions for Hebrew, getting started. But I just used settings on my laptop and added a second language and a key combination that switches between languages. On my android devices I use Swype app and have four languages installed (including two versions of English, US & UK. I just pick the languages in the settings and then to switch hold the spacebar for a second.