Lock and locate your lost phone

Use Android Device Manager (ADM) to find the approximate location of your device and when it was last used.

1. Sign into the Android Device Manager website at www.google.com/android/devicemanager, and ensure your current mobile device is selected.
2. From here, you can see the approximate location of your device. You can also lock the phone, erase your data, or ring your device. Your phone will ring for up to five minutes even if it’s on silent.
3. To quickly find your phone in the future, you can always ask Google to “find my phone.”

Source: https://www.android.com/phones/tips/#privacy-security