To delete users select “Manage > Users and groups” from the top menu and select the required user’s profile. On their profile page click the “DELETE” button.
NB When a user is deleted ALL existing data for that user will be deleted, including course attempts and scores, which means that:
the user will not be able to log in
the user will not appear in any reports
neither the user nor the account owner will be able to access that user’s certificates for any course.