While you can't easily set ChatGPT Search as a default search engine in most browsers (which you maybe shouldn't do, anyway), you can still create shortcuts to quickly and easily search anything ...

Do an inmate search If you’re using the Internet to find someone, you likely don’t know much about them—if nothing else, you clearly don’t know them well enough to easily contact them.

You can change default search and add Search Providers like Google, etc, to Internet Explorer in Windows. Learn how to manage Search Providers in IE.