By default, Firefox’s location bar suggests existing bookmarks and previous browsing history. If you find this to be more than you want to deal with, you can disable the suggesting of bookmarks, browsing history, or both.
1. Open Firefox.
2. Go to the menu, click on Tools and select Options.
3. Go to the Location Bar section.
4. Use the When using the location bar suggest dropdown to select what you want suggested. Choices are History and Bookmarks, History, Bookmarks, and Nothing.
5. Click the OK button.