Google is not just a search engine it has many tools as well. I am sure you know about G-mail but it is Google Docs that you should now be using to create "Documents" (.doc) "Presentations" (.ppt) and "Spreadsheets" (.exl). These files (or "docs") can be accessed through many apps. Google updates and changes so fast I cannot keep up with it. But it seems to always work somehow. The links and features are there. Keep looking.

Remember to LOG-OUT of Google from inside of any app that uses Google.

"Google Docs" is a generic term used to refer to all documents in your Google account. It is now called Drive and you can install a folder/app to update/sync on your computer and device.
The Google App does access your files and I have found it crashes often and is not very reliable. Using the "Desktop Version" in Safari seems to work better than the Google App/Browser. I believe it is much better to use an App such as Office HD save your file locally and then upload it to Google Docs/Drive and access it from there at home.

Canvas (the website) has a feature which enables you to access your Google Docs. So create your assignment using whatever means - Save it to Google Docs. Log in to Canvasand turn it in.

Many/Some apps will allow you to save or access your Google account to see/save to your "docs". If you use one of these (Office HD) BE SURE TO LOG OUT and/or UNLINK your Google Doc account.

The following APPs are on our school iPads and access Google Docs.
Our Word processing app. Both imports and exports from Google, Best bet is to create your document IN the APP save on the iPad and THEN move it to Google. You can then access it from a computer or other device and do what you need to with it.
A flashcard app that imports FROM Google Docs. Create a just a simple 2 column spreadsheet with words and definitions. Sure you can use Office HD - save it to Google docs. Now import it into this app and you have flashcards.
Sundry notes
Imports FROM Google Docs but does not export to it. Dumb.
A good little app but has limited storage/file output.
Canvas can access your Google Docs. Save your document to Google. Log in to Canvas and turn your work in to your teacher. Never touch MS Word or a computer!

Below are some other "Google Doc Apps" that I have found we may or may not have them.