Search browser

It is not. On iPhones the default browser is Safari, this icon:

It does however use the Google website as its default search engine. You accept that by simply using the iPhone and its software and accepting its terms of service.

You can change that in Settings->Safari->Search Engine to one of the other search engines available there if you want to.

Google is a search engine, not a browser. Are you asking about the Chrome browser from Google or are you asking about the default search engine?

So change it.

https://www.google.com/amp/s/9to5mac.com/2018/07/30/iphone-ipad-how-to-change-default-search-engine-in-safari/amp/

Your default search engine is Google. Your default browser is Safari.