The default search engine in edge browser is Bing. You can change this to Google / Yahoo etc. Follow below steps to change the default search engine in edge browser.
Open Search Settings
Open following url in edge browser.
edge://settings/search
This will open Address bar settings page. On this page you can select default search engine for Edge browser.
In below image, I have selected Google as default search engine.
Done. You can now close settings page and check new search engine by searching something from browser address bar.