Microsoft Word is an Office365 documentation tool.
Combined with OneDrive, Microsoft Word is an ideal tool for collaborative writing and e-feedback. By saving a document in your (organisation's) OneDrive, you can share the document with others, which allows you to work on the same document or provide feedback real time.
Example of an assignment using Microsoft Word:
You are going to write an essay on the (dis)advantages of communicative language teaching. Set up a Word document and save it to OneDrive. Share your document with a peer and with your teacher and write the essay together. You can ask for feedback on your document during class.