Teachers can create a Google Doc as a template for students and share it for them to work on.  Share the document with students as viewers and they can make their own copy.  Just make sure they share it with you so you can view their work!   An even easier way is to use Google Classroom since you can make a copy for every student that is automatically shared with you! 

Students can collaborate together in a Google Doc.  Since collaboration is a main focus for Google Docs, it's very easy to work together.  Students can see updates as others type along with who is typing.  Teachers can also see a version history of everything that has been added to the doc even if it is deleted!

Many teachers even use Google Docs to plan with their team since everyone can be writing at the same time!

Have a student who struggles with writing or wants to start verbally brainstorming?  Google Docs' Voice Typing feature is a great way to help them get their ideas written down.  Once they have their ideas down, they can go back and edit their work.  They will need to add punctuation, capitals, and check for grammar errors, so they'll still need to focus on writing strategies if it's their final copy.