How do you set parameters for articles and other content items?
From Joomla! Documentation
This article is for Joomla! CMS Version(s) 
In Joomla!, many Article parameters, such as Show Title, Show Author, and so on, can be set in three places:
- The individual article (the Article:[Edit] screen)
- The menu item (Menu Item:[Edit] screen)
- Global parameters (Article Manager / Options)
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.