Article: The "Find my iPhone" feature has been available for years, but is only enabled by default in iOS 8. If you are using an operating system from before September 2014, this method will only work if you enabled "Find my iPhone" through "Settings" → "iCloud," or specified that you wanted Find my iPhone enabled when you set up your device for the first time. Find my iPhone can only be enabled after linking your iPhone to an iCloud account, using the same settings menu. Log on to icloud.com, then click "Find my iPhone." If you are using another phone or tablet, you can instead download the Find my iPhone app from your device's app store.  Neither the app or website are available on Android phones or tablets. "Find my iPhone" apps for Android are not made by Apple, and are typically very slow and buggy.  You can access the website on any computer operating system, not just Mac. Click the image of the stolen device. Even if the phone has all the necessary settings enabled, it will only appear if it is turned on and has a working signal. If the phone is not listed, try again periodically to see if the thief has turned it on. Unfortunately, clever thieves can set the phone to airplane mode so they can crack your passwords without being accessible to this service. Don't assume that your data is safe just because you don't see the phone listed. If location service settings were enabled on your phone (as well as Find my iPhone), it should appear as a dot on the map. A green dot means the phone is online and the dot shows its current location. A grey dot means the phone is offline and its last known location is displayed. With the stolen device selected, click the small blue "i" icon. There are several ways you can protect your phone using the menu items listed. Using them in the order listed below is recommended:  "Remote Lock" or "Lost Mode" will set a new 4-digit PIN required to access your phone. Remember this PIN so you can access your phone if it is retrieved. "Send Message" will display a message on the screen. Typically, this is used as a warning that the phone's location is known, and/or a promise of a reward if the phone is returned anonymously. (You can also "Play Sound" to alert the thief that there is a message.) "Remote Wipe" is a last resort option that will remove all data from your phone, returning it to default settings and deleting all non-default apps. This should still allow you to track the phone if it is in "Lost Mode," but some users report issues.

What is a summary?
Use this for iOS 8, or if you enabled Find my iPhone. Log in to your iCloud on a computer or another Apple device. Select the stolen phone. Use the map to find your phone's location. Use the available settings to protect your iPhone.