Customize menu > Preferences > Preferences Settings dialog > GCS panel > Global Coordinate System group > Define > Category Manager
The Coordinate System Category Manager dialog enables you to create, edit, or delete a coordinate system category.
Categories—Lists the description of existing coordinate systems.
New—Displays the New Category dialog, where you can create a new coordinate system category.
Edit—Displays the Edit Category dialog, where you can modify a coordinate system category.
Remove—Deletes the selected coordinate system from the coordinate system library.