Menu Item Settings > General
By default, all of your menu items with submenus will inherit the trigger set in your Control Panel settings – Hover, Hover Intent, or Click.
This setting allows you to override that setting on a per-item basis. So if you have 10 items, 9 of which should be hover and 1 of which should be click, you would set the general Control Panel setting to Hover, then use the Trigger Override setting on a specific menu item to turn just that item into a click-trigger.