Each user is assigned a username when you add a new employee. To login, the employee just needs to enter this username and password on the login screen. To invite one or more employees to login, click on the "Invite" button on the employee list and you can either invite all employees or just a few selected ones. Each user will receive an email with their username and password. If your employees do not have email addresses, you will have to provide them with their username and password.