Microsoft is pushing big into the mobile space with hardware and with Windows 10 Mobile. They are also pushing really hard to get Office on as many Android devices as they can - and as a result they have just partnered with 20 more Android tablet makers to get this pre-installed. This is fully functional and "free" but if you want more storage and the best experience, you should probably give them money and become an Office 365 Subscriber. At least that's what they are hoping.
The move is the latest in the “mobile-first, cloud-first” strategy spearheaded by Microsoft CEO Satya Nadella. Over the past year, the company has launched Office applications that expand the reach of its productivity suite beyond Windows devices to Android and iOS. It comes alongside another announcement Tuesday that Microsoft will be bringing its Cortana virtual assistant to other mobile platforms to accompany its appearance on the desktop in Windows 10.