If you have lost your Android device there is an option to locate, ring, lock and even erase the data on it, remotely. Use the web browser from your desktop, laptop or any device and just load the Android Device Manger page.
Every android device has a primary gmail account associated with it, now this is an optional process but if you want to use the android OS to the full extent, you need to enter your gmail id for the first time. So by default every one of you have your handsets registered with Google and it can be accessed using Android Device manger.
Load this android device manager page from any browser, you will need to login to your gmail account – once done you will get to see your device or list of devices in case you have used multiple android devices before.
Select the model (in case there are multiple devices –by default you should see the last device or in other words your latest handset / tablet) , you can then check the last location (GPS should have been enabled on the device). Now you will find few options like ring, lock and ease. Using Android Device Manager you can ring your device, lock your device and erase the data on the device.
The Lock option can also be used to reset your device (replace lock screen password) in case you have forgotten your password – now this feature may not work on all devices. Moreover for this to work your handset should be connected to the net. If you have forgotten your password and data is off then you can at the most enable WiFi, and if you had already setup WiFi, it may connect even in locked mode.
Android Device Manage also gives you the last location / can help locate your device or performance a factory reset remotely. But for these features to work you need data and/or GPS enabled on your device. Hence it is always better to keep data and / or GPS on when you are traveling- this might come handy in case if your device gets lost or stolen.
Do Note: Android Device manger will work as long as your account is on the lost / stolen device.