An alternative collaboration option is Dropbox Paper, still in beta, but working nicely.
It’s a simpler and entirely browser based way to share a document plus messaging/comments on the side.
Documents can be shared with people, all of whom can view/edit the document at the same time in their browser. No software requirements or compatibility issues.
The document editor has all the things you’d expect plus some nice touches like a left-hand + bar to insert images, video, tables and even code blocks.
Also Task Lists with check boxes.
There’s some colorful extras like emoji’s and even, Microsoft take note, animated GIF support.
Think of it as a hybrid of Word and OneNote with instant messaging added to the mix.
Dropbox Paper seems intended as a place for ideas, planning and setting tasks rather than a more structured document creating and editing process.
Dropbox Paper is available to Dropbox users, look for the Paper item in the left-column of a Dropbox account.