Mark Hachman, writing for Macworld:

What Microsoft settled on to divide mobile and desktop users was screen size: specifically 10.1 inches. Anything smaller than that and users can pretty much do anything they want with the appropriate iOS, Windows, or Android app, including creating, editing, or sharing documents. But if you’re using the Office apps on a device whose primary screen is larger than 10.1 inches, Microsoft won’t let you create a new document, just edit and view an Office document created elsewhere.

That leaves the 12.9-inch iPad Pro as the only Apple tablet that doesn’t get to use this loophole.