Microsoft has teamed up with Dropbox to offer the users of the version of Office for iPad, along with the free version of Office for iPhone users, a quick way to both save and sync their documents and files on their Dropbox cloud storage account. The new feature will be added in an update that's due out in the next few weeks.
So why offer Dropbox support when Microsoft already has its own cloud storage service, OneDrive? Microsoft already knows that's where you're keeping Office files anyway:
With data and mobile usage exploding globally, millions of people are turning to Dropbox and Office to access, manage and collaborate on their files from anywhere, anytime. Over 1.2 billion people use Office to get work done, and Dropbox has become home to more than 35 billion Office files.