From Joomla! Documentation
This section lets you modify all currently selected (checked) items in one batch operation.
- Set Access Level. Select an Access Level to be applied to all selected items. See User Access Levels for more information.
- Select Category for Move/Copy. Select a target category where selected items should be moved or copied.
- Copy. Select this option to copy selected items to the specified category.
- Move. Select this option to move selected items to the specified category.
- Process. Proceed with the specified changes on all currently selected items.
- Clear. Reset all options in this section.