Group subscribe is only applicable for public type of groups. Create a menu item pointing to “groups” and select the appropriate category to display the list of public groups.
The public groups will be displayed as below

For each group the group id, group name, since, group image, description and member count will be displayed. The subscribe link is used to subscribe and unsubscribe to/from the group.
Subscription can be done in 2 ways. Allow unregistered members to subscribe or only registered members can subscribe and unsubscribe. We recommend setting the group subscription only for Registered Members.
If the public visitor is not registered and if clicks the subscribe link, then he will be prompted with the joomla login/register page.
Once the member get registered and login he can able to see the subscription page as below.

The name and the email address will be automatically populated by the system. The member can only input the mobile number and a short message to the group owner. Once the submit button is hit the member will be subscribed to this group.

The details of the member will be stored under SMS Contacts of the respective owner of the group member.
The contact will be published / unpublished depending on the value in “Auto Approve” field.