Lost Mode locks your iOS device with a passcode and can display a custom message and contact phone number right on the Lock Screen. While in Lost Mode, your device can keep track of where it has been and report back so you can view its recent location history, right from the Find My iPhone app.
If your iPhone or iPad is missing and would love to lock it using the Lock Mode feature of Find My iPhone, follow me through the steps below:
1. Sign in to icloud.com/#find with your Apple ID (the one you use with iCloud).
2. Click All Devices, then select the device you want to track or lock.
3. Click Lost Mode (iOS 6 or later), or Lock (iOS 5 or OS X v10.7.5 or later).
4. Follow the onscreen instructions, keeping the following in mind:
==> If your iOS device already has a passcode, that passcode is used to lock the device.
==> If you’re asked to enter a passcode, that passcode will be required to unlock the device.
==> If you’re asked to enter a phone number, enter a number where you can be reached. The number appears on the device’s Lock screen.
==> If you’re asked to enter a message, you may want to indicate that the device is lost or how to contact you. The message appears on the device’s Lock screen.
How To Turn Off Lost Mode on iPhone, iPad
You can turn off Lost Mode by entering the passcode on the device, or by clicking on STOP LOST MODE when signed in to www.icloud.com/#find.