From e-Learning Documentation
Canvas leverages technologies like Google Docs and EtherPad allow multiple users to work together on the same document at the same time. Collaborative documents are saved in real-time, meaning a change made by any of its users will be immediately visible to everyone.
Collaborations that leverage Google Docs require that all participating learners have created and linked their Google account to their personal Settings. Collaborations in EtherPad do not require students to set up any account. Students will be able to enter the document simply by clicking on the Collaboration link.
When would I use Collaborations?
You can use Collaborations to:
Copy and paste lecture notes that everyone can access.
Share with your students bullet-point lists or agendas for upcoming synchronous class time or meetings.
Create a text-based whiteboard that everyone in the classroom can see and refer to later.
Assign student groups a collaborative assignment. Require them to turn in the URL as a graded Assignment. Note: As an instructor, if you want to create a document for a certain group, create it within the group. Or you can create a Collaboration in the course by adding a group per document.