This article explains how to set up Find My (or its predecessor Find My iPhone) on your iPhone, iPad, or iPod Touch using iOS (or iPadOS) 13 or newer.

How to find your iPhone on an Apple device You can quickly track your iPhone on your iPad, Mac, or a family member’s iPhone. The first step is to open the Find My app.

Earlier versions of iOS, beginning with iOS 5 when Apple introduced Find My iPhone, follow similar instructions. Turn on Find My The option to set up Find My is part of the initial iPhone setup ...