You can use the Canvas Inbox to message your students. The Canvas Inbox is not the same as e-mail, though. It is a messaging tool where students can send/receive messages in the Canvas environment. However, all users in Canvas can choose to be notified via e-mail when they receive a message via the Canvas Inbox. Also, unlike standard e-mail, you cannot send/receive messages via the Canvas Inbox from friends/family, because those folks most likely are not enrolled in the course that you are enrolled in. So, how do you send messages to your students? Here are some Guides that should help:
