If you signed up before Aug 9, 2021, please click Previous plans to view your applicable plans.
Yes, In case your helpdesk agents also go out into the field to help customers, you can add them to service groups.
This ensures that any service task you assign to a particular group can be picked up by the helpdesk agents in it as well. This will also allow helpdesk agents to view their service tasks like any other ticket through their mobile apps.