The administrator has to first register the user in the application. For help on registration, see http://www.digite.com/swift/help/creating-users/
You can then invite the user to your project.
To invite a team member:
1.Navigate to your project either from Quick Links widget, or click Projects and double-click the project row from the list.
2.Roll over the Project name in the breadcrumb, and click Team Member.
3.Click the Invite icon on the toolbar.
4.Type in the email id of the user you want to invite or click the name which appears as you type the name in the Invite Team Member window.
5.Click Invite. The team member will receive an invitation mail and the team member will now be listed in your List of Team Members page indicating that the member is assigned to your project.