If you have configured your Google Group so that people can request to join your group, then you as a Google Group Manager will need to approve the join requests.

When someone applies to join your group, all Group Managers will receive an email with the subject Member requesting to join <group name>.

1. Open the email.
2. Click the Manage members button.
3. To the right of their name click Approve request or Reject request.

You can also check any pending members from the Groups web UI without relying on the email notification.

1. Visit Google Groups.
2. Click My Groups.
3. Click the name of the group you manage.
4. From the navigation menus on the left side of the screen, click Pending members under the People category of settings.
5. To the right of their name click Approve request or Reject request.

For further Google Group support help, please see Google's Groups Help page.