Recovery, in Android, refers to the bootable partition, in which the recovery console is installed.
It contains tools to help repair your installations as well as install official OS updates by using a combination of key presses or instructions from a command line sometimes.
Android is open, meaning the recovery source code is available, so that building a customized ROM is relatively easy.
1. For a start take your phone and hold down your power button to shut it down.
2. Then press volume down button and power button and hold them untill next step.
3. When you will see LG logo on your screen you can release those buttons.
4. Now you will enter recovery mode screen.
5. And this is it! You have reached your destination.
Recovery is included on a separate partition from the main Android OS on all Android devices.
You can boot directly into recovery mode and use it to factory reset the device, delete the cache partition, or apply software updates. It can help you fix your device.