By default in Firefox for Android, the Quit option doesn't display in the menu. By adding this option, you can automatically delete your browsing history and close all tabs every time you exit Firefox through the Quit option in the menu.

Add the Quit option to the menu

This option automatically deletes your browsing history every time you exit Firefox through the Quit option in the menu.

1. Tap the menu button
   
2. Tap Settings.
3. Tap Delete browsing data on quit.
4. Slide the switch for Delete browsing data on quit on.
5. Choose the types of data you want to delete when you exit:
   • open tabs
   • browsing history and site data
   • cookies
   • cached images and files
   • site permissions
   • dowloads
6. The Quit option now appears in the menu.