Bing is the default Search engine in Microsoft Edge, Windows 10 build 10158 now lets you add a desired search engine — excluding Google, YouTube and Yahoo — to Edge browser and set as default, but the following is the standard procedure to add and set a particular search provider as default in Microsoft’s new browser.
READ: How to import bookmarks from other browsers into Microsoft Edge
Changing the default Search Provider in Microsoft Edge
1. Visit Search engine site, click on ‘…’ menu icon, select Settings > View Advanced Settings
2. Scroll down a bit, under ‘Search in the address bar with’, click on down arrow, and from the list, select ‘<Add new>’
3. Under Choose one, select the site and click on ‘Add as default’.
ALSO SEE: Fix Can’t add Google as Search Provider in Internet Explorer 11
This way you can set DuckDuckGo Search as default in Microsoft Edge but not Google, let us see Microsoft allows us to do that when Windows 10 final releases on July 29th.
UPDATE July 15, 2015: Google gains OpenSearch Support, So you can now set it as default Search Engine in Microsoft Edge browser