Articles that have been archived in Joomla are hidden by default within the Article Manager. In order to locate these articles you need to specifically search for them.
1.) Log into the control panel
2.) Go to Content > Articles
3.) Click the Search Tools drop down button
4.) Click the Select Status drop-down
5.) Select Archived
6.) The Article Manager will now display all the archived articles within the system. At this point, their status maybe be changed to published, unpublished, or deleted like any other article.