What should have been done years ago, Microsoft have just announced Office for the iPad.
The new Office app will be available later today on the App Store. It is pretty similar to the iPhone version where it's free to read and present documents, but you will need an Office 365 subscription to create or edit any documents.
You'll be able to use Word, Excel and Powerpoint on the iPad and it has a very similar interface to what you see on the Windows and Mac versions. The iPhone version only gave access to basic editing, but the iPad version is much more developed, giving you as much control as you'll find on the PC and Mac versions.
Thankfully the apps aren't just a port from the Windows Surface tablets, it's completely natively built so it works perfectly in iOS.
However you have to wonder why Microsoft took so long to make this happen and why you would pay for a monthly or yearly subscription. Apple has been offering Pages, Numbers and Keynote for years now at a one off fee. If you recently bought a new iPad or MacBook, you get the set of apps free. And they basically do everything you'll find on Microsoft's Word, Excel and Powerpoint.