Chatter groups are places where you can collaborate with your project team members or customers. There are two types of Chatter groups:
To create a new Chatter group, follow these steps:
Go to the Chatter tab and click on Group or directly go to the Group tab.
Click on the New Group button.
Enter Group Name and Description (the group name must be unique).
You can also select the Automatic Archiving option for your group. There are two options:
Archive this group if there are no posts or comments for 90 days
Don't automatically archive this group
Click on the Save button.