Office for iOS support for the iOS Document Picker
Office for iOS integrates with the iOS Document Picker by means of the Document Provider extension, which enables Office to open files stored by another document provider.
Versions of the Apple iOS starting with iOS 8.0 include app extension support. You can use these extensions to expand the functionality of your application into other apps or contexts on the user's device. To integrate Office for iOS with the iOS Document Picker, you use the Document Provider extension.
The Document Provider extension supports four operations:
Office for iOS integrates with the open operation. When you create a Document Provider extension, your users can use the Document Picker to open and edit documents directly in Office without creating a duplicate copy of the file.