Canvas Support

Once Chat has been enabled in your course, the Chat tool can be used for real-time conversation in your course. Any user in the course can initiate a chat conversation. Although any user can join a chat, the tool’s recommended limit is 50 participants.
All content in a course chat, including the chat history, can be viewed by anyone in the course.
A user must be actively viewing the chat tool to appear in the chat list. If you are an instructor, you may consider posting chat hours in the course calendar to let students know when you are available. Or you can open Chat in a new browser window while viewing other areas in Canvas.

NOTE:  If you cannot view the Chat tool, Chat has not been enabled for your institution.