How to view iCloud Drive files on your iPhone and iPad
New with iOS 9 is the iCloud Drive app. Yes, all the finaly-s! It lets you see everything and anything stored in your iCloud Drive on iPhone, iPod touch, iPad, and even Mac. (It basically turns the DocumentPicker interface into its own app.) For some inexplicable reason, though, the iCloud Drive app starts off hidden by default. You're given a chance to show it when you first update, but if you miss it, you can still turn it back on at any time in Settings. And most people should!
Full story from the iMore Blog...