The Office Mobile apps are optimized for touch—no keyboard or mouse required. With a pared down set of features, the mobile apps are ideal for reading, reviewing, and editing Office files when you're away from your desktop PC.
The OneNote, OneDrive, and Outlook Mail and Calendar apps are already installed on your phone (look for them by swiping over from Start to the All apps list). For the others, go to Microsoft Store and search for office. You'll find familiar favorites like Word Mobile, Excel Mobile, and PowerPoint Mobile, as well as newer arrivals like Sway.
For more info, see the Office Mobile Quick Start Guides.
Office Mobile apps on tablets, PCs, and phones