Hello, to set a default search engine Tap the Menu button (either below the screen on some devices or at the top-right corner of the browser) . Tap Settings (you may need to tap More first) . Tap Customize, then Search. Tap the search engine that you would like to set as default and choose Set as default. To Add search engines As you type in a search, Firefox for Android will suggest multiple search engines for you to use. If you don't see your favorite search engine on the list, follow these steps to add it: Go to the site of the search engine you want to use. For example, youtube.com. Tap and hold inside the search box and tap on the magnifying glass icon . To Remove search engines Tap the Menu button (either below the screen on some devices or at the top-right corner of the browser) . Tap Settings (you may need to tap More first) . Tap Customize, then Search. Tap the search engine that you would like to delete and choose Remove.