I get the message that WriQ only works inside a Google Doc

If you open a Google Doc from the Classroom Student work window and try to use the WriQ extension you will see the following message:

When you open a Google Doc from the Student work page, it opens with the URL https://classroom.google.com which will not allow any Chrome extensions that are setup to work with Google Docs. 

Currently, Chrome extensions are not available with the Classroom URL and can only work with Google Docs that are opened with the URL https://docs.google.com/document/

To open a Classroom Doc into a Google Doc window, you can use the Open in a new window option under the Comment bank on the right side of the turned in screen. This will then open a https://docs.google.com/document which will allow you to use WriQ.

You can also open these Docs from your Classroom folder in Google Drive and use WriQ.