Other than the three groups that come by default with Jira, you can create your own groups. It is important to note that once you create a group, you cannot change its name. Therefore, make sure that you think about the name of the group carefully before you create it:

1. Browse to the Group Browser page
2. Enter a unique name the new group in the Add group section
3. Click on the Add group button to create the new group

After a group is created, it will be empty and will have no members; you will need to manually add users to the group.