Firefox whether as mobile versions for Android and iOS/iPadOS or as desktop version for Windows, macOS, Linux is a web browser and not a search engine. Mozilla does not have a search engine of their own. Manage my default search engines in Firefox for Android https://support.mozilla.org/en-US/kb/manage-my-default-search-engines-firefox-android If you want to make Firefox the default web browser on Android then see https://support.mozilla.org/en-US/kb/make-firefox-default-browser-android