The member is a person that you have invited to join your team site. Each member that you invite to join your site will use one of your licenses.
To invite someone to your site, simply Select ‘Admin’-----> ‘People’-------> ‘All users’ and click on the ‘Add a Member’ button.
Fill in the form by adding the details of the person that you want to invite and click ‘Add Member.
The member invited will receive an email inviting them to join the team site.