F12 tools provide a set of tools that you can use to design, debug, or view webpage source code and behavior. F12 tools can be opened in a separate window or pinned to the bottom of the webpage that you're debugging.
In Search settings, enter Developer Tools. By default, the Open the DevTools when the F12 key is pressed setting is toggled on. Choose Open the DevTools when the F12 key is pressed to toggle the setting to off. Select F12 to confirm that DevTools no longer open.