is Firefox secure?

Firefox for desktop Windows, macOS, Linux and mobile versions for iOS/iPadOS and Android are web browsers. Mozilla the makers of the Firefox web browsers does not have a search engine of their own. A search engine is for example duckduckgo.com, bing.com, google.com etc. https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox Since you posted this thread with Firefox for Android https://support.mozilla.org/en-US/kb/manage-my-default-search-engines-firefox-android