You can give access to other people so that they can access the software and manage an employer.
To get to the appropriate page, click the employer name in the main navigation and go to Settings -> Users.
Access is granted on a per-employer basis. So if you're managing multiple employers then granting a user access to one employer wont also give access to other employers.
To give access to somebody, click the "Add User" button.
You'll be asked for an email address and given the opportunity to edit the default message.
Be sure to select the correct role.
An email is then sent to the address provided telling them they've been granted access.
If you want to revoke an invitation before it has been accepted then you can easily do so.
Switch to the "Invitations" tab and click "revoke" next to the appropriate invitation
If the recipient of the invitation doesn't already have an account they'll need to register to create one using the exact email address that the invitation was sent to.
Once logged in they'll see a notification that they have an invitation. If they haven't already done so then they'll have to verify ownership of their email address.
The user can then choose to either accept or decline the invitation.