The default search engine in the browser app on the OnePlus smartphone is Google, which can be changed at any time according to your wishes or needs, for which we have the following options or search providers available:

Android 10 | OxygenOS 10.0
Step 1:  Open the  Chrome app
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  Search engine
Step 5:  Choose a  search engine
  1. Open the Chrome app
  2. Open the menu
  3. Open the Settings
  4. Tap on Search engine
  5. Choose a search engine

OnePlus Instructions