You are probably aware that Apple has introduced a 10.5" and a 12.9" version of the iPad Pro. What you might not be aware of is that Office 365 (for Word, Powerpoint, etc.) will no longer run free on these two sizes. Microsoft considers that any screen size over 10'1" to be commercial in size and requires a license. More info here.
However, there may be a way around this. If you should need to use Office 365, you can open up a free Microsoft account, then download and use Office Online, here. This gives you most of Office 365, and it's free.