This panel contains settings that affect the use of categories in all of your collections.
Allow moving categories
If checked, this option allows you to move a category from one collection to another in the Category editing screen.
Warning: You have to be careful about enabling this option though as doing so can break pre-existing permalinks.
For information on using categories with your posts, please read: Post Categories Panel.
For additional information on how to move a category between collections, please read: FAQ: Move a category