Microsoft made good on their promise to bring Office to Android tablets. They just made the Office Preview available for Android tablets and you can get it at the Google Play Store. This "Preview" version is basically like an extended "beta" test, although most of the kinks have already been worked out. The program is designed to get feedback from users so Microsoft can improve upon the Android tablet version of Office.

There are a few limitations worth considering before trying out this Office Preview. Here's a quote from Microsoft's blog with the full details,

In November, we invited you to sign up for the Office for Android tablet preview. With such an overwhelmingly positive response from people around the world, we made it even easier for customers to download the preview apps by requesting access to the Google Plus community.

Over the last two months, we have heard from people all over the world who want the power of Office on their Android tablet. The feedback we’ve received through this initial phase of preview has helped us shape and optimize the Office experience for Android tablet users. Your feedback also helps us plan and prioritize future feature updates.

Today, we are excited to announce that we are further expanding the preview. We want more feedback from more users to ensure that Office apps work well on a range of different Android tablets before launching the official apps. To participate in the preview, you can use an ARM-based Android tablet running KitKat or Lollipop, with a screen size between 7″ and 10.1″. Starting today, anyone can go to Google Play and download the Word, Excel and PowerPoint preview apps. No waitlist. No requesting access. Just go and download the apps!

We hope you will join the preview and tell us what you think. Your feedback is critical in helping us deliver world-class Office applications to Android tablets. Download the Word, Excel andPowerPoint preview apps for your Android tablet today and tell us what you think in our Google Plus community.
Finally, keep in mind that the "preview" versions of Office are actually broken up into Office's constituent parts. Word, Excel & PowerPoint must be downloaded separately: microsoft office preview - Google Play

Source: Microsoft Office Blog