I havent used office in a many years now.. but I thought MS Office is now an online offering similar to Google Docs?
If you use OneDrive, then you basically get just the web apps for documents stored in there (which is also the easiest way to check out).
Although the core product is still desktop based, they've been shifting to an optional subscription model where you pay $9/month or so for perpetual updates and 1tb of storage.
The old installable still exists and many features only exists in that version. The offline version has also become a lot easier to install.
The web app version is lacking in a number of ways and was buggy last I tried.
I haven't needed to do anything complicated, but I can open a document that someone's used "Track Changes" on, and modify it etc.