How do I find Safari on my iPhone?

Safari is built in, and cannot be deleted.

You can look for this icon:

You could have moved it onto another screen, into a folder, off to the App Library.

You can use Spotlight search by swiping down from the middle of the screen. If its in a folder it will tell you which one.

Otherwise, you can swipe all the way to the right to the last home screen and look for Safari there. You can then just drag it back to a home screen.