If you want to setup a new user that's going to take care of invoices, you will also need to setup a contact. Users can't receive email notifications (for new invoices for example). That's rather inconvenient.
set email notifications for users
Currently there is no way to set email notifications for a user, so if you want other users to get certain email notifications, such as invoice reminders, then the only way to do this is to set them as a contact as well.This has been confirmed by WHMCS staff.Please can this be added so that users can have the same notification settings as contacts, as it rather defeats the point if you also have to add them as a contact.