I suppose you could install Word. If you want just Word, you can jump through a few hoops to make the Office Deployment Tool install only Word.
I don't think that is a reasonable solution for your use case, but I suspect making people use (and buy) the actual Office Suite is the motivation.
Edit: I see my point has been phrased poorly - I was trying to outline that I suspect MS' point is making people get Word (Office) instead. Maybe I'm just plain wrong on that though.
Installing Word, on a server, running as administrator, forecefully linked to some MS account for activation... Is that really a reasonable solution in a Microsoft world? Smh.
If documentation comes as Word document there is no documentation and a huge red flag for the software.