MacBook Pro 2015 won’t download ANYTHING

So I am used to tablets iPads, iPad Air, etc. but for some reason I cannot for the life of me figure out how to upgrade or whatever I have to do for this computer/laptop so I can download Microsoft 365. At this point I would just take Microsoft even though I would really prefer Microsoft 365 or I would’ve got another computer, but I can’t even download any other apps either please somebody help me. I’m on a deadline tomorrow evening. I just got a promotion as a free rant, lance writer Higher pay and if I don’t have the story and I probably will get fired