Enable additional search box in browser

A search box is another text input field located next to the address bar in a web browser. It allows users to perform web searches directly from the browser interface.

If you enable or don't configure this policy, the search box is visible and available for use.
Users can toggle the search box in Microsoft Edge Settings page edge://settings/appearance#SearchBoxInToolbar.

If you disable this policy, search box won't be visible, and users have to use the address bar or navigate to a search engine to perform web searches.