Google Drive provides a suite of office tools that all exist in the cloud - accessible anywhere, anytime, from any device.
You can access your Docs, Sheets, and Slides all from Drive without internet access by turning on "Offline" access. Simply turn on with a wireless connection, and the next time you lose internet you will be able to access files. (Will not work with Word documents in Drive.)
Google Docs + Digital Feedback (Kaizena - Digital Writer's Notebook)
10 Things Every Teacher Should Know How To Do With Google Docs
Here's a quick 1 minute demo of each:
Here's a full demo of each: