Microsoft Word is a part of Office 365, which gives you 1 TB of online storage and costs $6.99/mo. You can use it on Windows, Mac, iOS, and Android. You get Excel and One Note, too, which can help you organize notes/data. What I really like about it is that all my files are autosaved to the online storage so I don't have to worry about losing work. Also if I'm reading/editing away from my computer I can pull up my phone and check something very easily. You can also access/edit your documents in your web browser, kind of like Google Docs, so you can access your files on any device. But I also live in a place with good Internet/cell signal so connectivity is never an issue for me. Compare this to Dropbox, where you only get 2 TB of storage for $11.99/mo, it's a really good deal. Word definitely has trouble when you hit 150k words+, but so does Scrivener if you have it compiled as one thing.
Google Docs is free and the word editor is decent. I have friends that write exclusively in it because they can access it/write from their phones easily (but you can do that with Word, too.....). It's very, very easy to share your documents with other people and for them to leave comments/editing (Word has this, too, but there's a few extra steps and can be confusing for people not familiar with it) so if you plan on being collaborative, that is a good choice. There is a way to have your documents saved locally to your computer so you can edit them offline, but that takes foresight to do so, like if you're going to a cabin for the weekend that has no Internet.
It's been many, many years since I've used Open Office or Libre Office so I can't speak on them, also I'm exclusively on Windows. Personally, I use Word for shorter works and Scrivener for longer ones, as it's way too much program for something small. I actually wrote the 190k word first draft of my manuscript entirely in Word; I only got Scrivener because I knew rearranging scenes/chapters in Word would be a horrible time. But if you already want some way to back up your important documents/photos, then Office 365 really can't be beat for the value. I know I probably sound like a salesperson but I promise I don't have a vested interest in Microsoft or anything like that.
