If your iPhone is lost or stolen, Apple offers a free tool to help you recover it. Even if you don’t get your phone back, you can use the tool to prevent a thief from obtaining your personal data. This iPhone recovery tool is called Find My iPhone. It’s part of iCloud and uses your phone’s GPS and internet connection to locate it on a map and perform a number of actions remotely.
How to Find a Lost iPhone Even If It's Dead or Offline (Dec 2022, iOS 16)
The Find My iPhone service must be set up on your device before it is lost or stolen. Once the service is set up, there are two methods to locate a phone: use the iCloud website or the Find My iPhone app (open this on any iOS device to track your phone).
Here's how to use Find My iPhone via the iCloud website:
Go to iCloud.com and sign in with the same Apple ID you use on your iPhone.