Losing an expensive phone such as an iPhone can be a nightmare, especially if you have sensitive data stored in it. In order to find someone else’s lost iPhone through Find My iPhone, that person must’ve turned on Find My iPhone prior to losing the phone. To check if Find My iPhone is on, go to Settings > tap your name > Find My. If that option was never turned on, then it’s going to be impossible to locate a missing iPhone through the Find My iPhone app; unless it’s located by playing a sound on the phone through the app.
Use Find My iPhone for someone else
To use Find My iPhone to track someone’s iPhone, you first need to make sure that the person you’re helping knows their iCloud email and password. There are two ways of tracking someone else’s iPhone: through another iOS device; or through a web browser. The easiest way of finding someone else’s iPhone is through another iOS device such as an iPad or another phone. But if you have a computer laying around, it’s also possible.
Using Find My iPhone to find another iPhone
In order to find another person’s iPhone, you must have the Find My app installed on your iOS device or Mac computer. Although this app comes pre-installed by default, it can also be deleted by the user. If the Find My app is not found on your iPhone, you can download it from the App Store. Launch the app, click Me at the bottom of the screen, and tap “Help a Friend.” This option will redirect you to the Find My device website. Once in there, type your friend’s iCloud information.
Since the page knows that you’re looking for a missing device, it will not ask you for Two-factor authentication.
Find My iPhone on Mac/computer browser
In case you would like to locate an iPhone on a bigger screen or don’t have access to the Find My app, you can locate a device through any computer’s web browser. To do this, you must sign in to iCloud from icloud.com/find. If you try to sign in directly through iCloud using another URL, it will ask you for a Two-factor authentication code, which you obviously don’t have.