In Edge, click the menu, go to "Settings" > "Privacy, search, and services" > "Address bar and search," and then select "Bing." In Chrome, click the menu, go to "Settings" > "Search Engine," and select "Bing." In Safari, click the Safari menu, go to "Settings" > "Search," and select "Bing."

Click the three-dot menu on the top right. Click Settings. Select Search Engine. Select the engine of your choice from the list of search engines in the drop-down menu. If the browser search engine keeps resetting back to Bing despite that, you'll need to remove the adware or malware responsible.