HR can invite employees using e-mail (1 invitation for 1 stated e-mail). There is also another option. You can go Employees -> Add employees -> Import xls. In the window you can see the template and choose file to be uploaded to the service. System will add users (employees) to your company and table will be shown on the page Employees. In the table you can choose role for each person and send an inviation to e-mail.