What does it for? In the past, a phone is more of a device used to make calls or text. However, it's much more than that.
Most Android devices are now defaulted with a fairly simple Recovery mode with features like Reboot System Now, Apply Update from ADB, Apply Update from External Storage, Wipe Data/Factory Reset, Wipe Cache Partition, Apply Update from Cache.
Just like a lot of other things with Android, even the Recovery Mode can be customized to do more things.
1. The beggining of the hard reset process is based on powering off your device.
2. When your phone is turned off you have to press and hold both Volume down button and power button at the same time.
3. When LG logo will appear on screen release both buttons.
4. Now there should be a recovery mode menu on your screen.
5. Here use the Volume buttons to scroll through the option and use the Power button to choose the highlighted area wipe data/factory reset.
6. And now your phone will restart itself so please wait patiently. Good job!
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.