I happened to notice this addition yesterday because I updated my Nexus 5 to Android 5.0 and then reset the device and reinstalled all my apps: Microsoft this week updated Office Mobile for Android handsets to support Dropbox integration. But there's another change I hadn't noticed as well. The update lets you share files with others too, regardless of which service you use.
You may recall that Microsoft announced its partnership with Dropbox earlier this month, and that the goal was to integrate Dropbox storage as a "place" within all of the Office applications across various platforms. At the time of the announcement, Microsoft said that Dropbox support would come to iOS (iPhone, iPad) and Android first, and that did quickly happen on the iOS side and, for those lucky enough to have it, the preview versions of the Office apps—Word, Excel and PowerPoint—for Android tablets.
So this week, Dropbox support was added to Office Mobile for Android handsets as well. It works and looks exactly as you'd expect, letting you add Dropbox as a place alongside OneDrive and OneDrive for Business, browse your documents on the service, open/save files to/from Dropbox and so on.
But here's the other new feature: You can also share files from Dropbox, OneDrive, and OneDrive for Business directly from within the Office Mobile for Android handsets app. And you can share either by link (URL) or by email attachment.
To share a document from Office Mobile for Android handsets, open it and then tap the More (three vertical dots) menu item and then choose Email as link or Email as attachment.