My friend's lost IPhone

If a friend's device is missing

You can help a friend find their device if it's missing and has Find My [device] turned on:

1. Open the Find My app.
2. Choose the Me tab.
3. Select Help a Friend.
4. Have your friend sign in to iCloud with the Apple ID they're signed in with on their missing device.

Axel F.

What app didn’t he have? Find My service is a setting, not an app. You enabled it by going to Settings/[user name]/Find My. It is turned on by default when you log in to your Apple ID when setting up the phone. If his is not on that means he turned it off. And if it is off there is no way to track the phone.

The Find My app is how you track a phone that has Find My service turned on; it is not required to enable Find My. And it is installed by default and cannot be removed.

He had to have had the Find My app but if you are saying he didn't set it up then there is no way to do so remotely.