You may need to add users to your Canvas course. You can do that as a teacher of the course by using the People tool. In the top right, you will find a +People button. When you click this, you will find an interface. Select NetID, type user’s Net ID (one per line), select role, select section (if needed), then click Next button at the bottom. You will arrive at a window indicating the users were found. Click ADD at the bottom to complete.
NB: You can add other instructors and TAs to any class this way. You can also use it to add students to a class not booked by the registrar. If you would like to add a student to a registrar booked class, please contact email@example.com so that the enrollment does not get erased when the system syncs with Banner.