Safari uses Google as its default search engine out of the box, but it's not the only option. You can choose other search engines like Bing, Yahoo, or DuckDuckGo if you prefer them.
What is the best search engine for Safari?
Google certainly does the job for most Safari users. It became one of the first search engines in the early days of the internet, and it's only gotten better. But there are reasons why you might want to consider a different option. DuckDuckGo does a better job of protecting your privacy.
What search engine does Safari default to?
While you can't change your default web browser on iOS, Apple does allow you to change the default search engine in Safari. The default on iOS is Google, but you are able to change it to either, Bing, Yahoo, or DuckDuckGo.