In Joomla!, many Article parameters, such as Show Title, Show Author, and so on, can be set in three places:
Typically, parameters at the individual article and menu item levels can be set to a specific value or to a value of "Use Global". If the individual article's parameter is set, then that value controls the setting. If this is set to "Use Global" then the menu item parameter is checked. If the menu item is set to a specific value, that value is used. If the menu item is set to "Use Global", then the global parameter setting is used.
A similar hierarchy is used for other content items, such as Banners, Contacts, News Feeds, and Web Links.