Right now you can download Microsoft Word, Excel, and PowerPoint from Apple’s App Store! It was a little hard for me to find but it is currently in the Featured section. Definitely worth checking out.
If you want to know more, a good place to start is: Satya Nadella’s press briefing webcast.
Just getting started with Word but I gotta say, “It’s sweet!” Unlike when I started trying to use Pages, in Word for iPad in short order I am feeling comfortable.
One tip: the second icon (right next to Back) is the File menu. In the File menu is help and the Help is great! I especially liked the Video: “Select stuff in Word for iPad” and the article “Use an external keyboard with Word for iPad”.