Use Find My iPhone
Find My iPhone enables you to find your mobile phone if you lose it or you can lock it should it get stolen. To use this function, you need to turn on Find My iPhone.
Connect to iCloud
Open an internet browser on your computer and go to www.icloud.com.
Find your phone
Click Find iPhone.
Click All Devices.
Click the name of your mobile phone.
Your mobile phone's latest position is displayed on the map.
To see your mobile phone's latest position, you need to turn on sending of your mobile phone's latest position.
Play signal tone on your mobile phone
Click Play Sound.
You can send a signal tone to your mobile phone which will be played back for two minutes. For the signal tone be played back, your mobile phone needs to be turned on and be connected to a mobile network or Wi-Fi network.
Lock your mobile phone
Click Lost Mode and follow the instructions on the screen to lock your mobile phone.
You can lock your mobile phone with a code and add a message to the phone screen saying that you've lost your mobile phone.
Delete all phone content
Click Erase iPhone and follow the instructions on the screen to delete all phone content. Please note that you will no longer be able to use Find My iPhone when you've deleted all phone content.
You can delete all phone content to prevent others from accessing it should your mobile phone get stolen. When you've deleted all content, your mobile phone needs to be activated using your Apple ID.