This feature is available in Catalyst, Enterprise, and Ultimate editions.
List Type Administration functions are only available to users with an Admin Privileges role of "System Administrator".
Select Admin > Project & Field Admin > List Types.
Select a List Type tab (Task, Test, Story/Backlog Item, etc.), and then navigate to the desired List Name section.
Click the Add button in the section to which you want the add the list type.
Enter the required information, and then click Save.