The iCloud Activation Lock
The iCloud Activation Lock uses your Apple ID and password to secure your phone from unauthorized access. What it means is that as the original iPhone or Apple device owner, it is only you who can bypass the activation lock by entering your iCloud credentials.
Activate Find My iPhone through your iPhone’s settings
Also, the original phone user can remotely lock the device if the phone gets misplaced or stolen. The remote lock is possible by just logging into your iCloud account, via the iCloud website, and turning on Lock Mode. The Find My iPhone feature will then assist in the process of trying to trace a lost/misplaced iPhone. The function also displays the phone’s last locations during the last twenty-four hours.