As of 2014, Firefox hides the toolbar by default to streamline and improve the view of the screen. To access it, press the keyboard shortcut "Alt + F". Click the Tools option. Click Add-ons, and a separate tab will open.
This option opens a list of extensions currently installed and running in Firefox. Click Disable or Remove to stop the extensions from running as part of your browser. Changes take effect once Firefox restarts.
Plug-ins can activate automatically or never activate, or they can require user permission. Set these permissions accordingly to manage plug-ins with or without permissions.
By clicking the Get Add-ons button and scrolling through the list, it's possible to add new extensions to Firefox to improve the browser's functionality. If you know the name of a specific extension, type it in the search bar, and Firefox can attempt to locate the download site. Click the Add to Firefox button if one appears.