As an admin, you can enable Open Registration for your entire account. Open registration allows instructors with the appropriate permissions to add users to a course, even if the users don't already have Canvas accounts. When an instructor adds a user to a course, the user is sent a course invitation. To join the course, the user must first register with Canvas and create a password. The user's account will then display in the account Users list.
Even with Open Registration disabled, admins with the Modify Login Details permission can always create accounts and add users to courses, even if they don't have Canvas accounts.
Once this feature is enabled, instructors can add users in the course People page.
