how do i delete google as my default search engine

Safari is an internet browser not a search engine. The internet browser developed by Google is Chrome.

If you want to make Safari your default internet browser, open Safari, go to Preferences on the Safari menu, click General at the top of the Preferences window and the first item in that window is where you select to make it your default browser.

Also, click Search at the top of the Preferences window and select your search engine there.