Using this form you can define the default role that users are assigned to when they register. If you define this as the applicant role, you can then further define the default role that users should be assigned to when they are approved for membership.
New member role
When new users apply for membership, this is the role to which they are assigned. If that role has Sign-in ability, they will be granted immediate access to the forum. If not, they will be assigned to a special “Applicant” role. You must then approve them for membership from their account. A summary of the number of new applicants should be visible in the panel on the settings tab.
Membership approval role