WARNING! When you reset the device, all your personal data located on the phone’s memory will be deleted. This includes media files, contacts, ringtones, downloaded content, apps etc. Additionally, all settings will be restored to factory values, however data located on the SD storage and SIM card won’t be affected.

NOTE: You can check this thread for a guide on how to back up data, and this thread for a guide on restoring data.

Factory Reset via Settings:

  1. Open “Settings
  2. Access “Phone Management
  3. Tap “Backup & reset
  4. Tick or clear the check box associated with “Automatic restore” and “Back up my data
  5. Tap “Backup account” and select the account you want to use for the backup
  6. Tap “Factory data reset
  7. Optionally, choose to “Erase SD Card” as well
  8. When ready, tap “Reset phone
  9. If your phone is protected by a lock screen, enter your password/PIN to proceed
  10. Tap “Delete all” > “Reset

Factory Reset via Android Recovery:

NOTE: If your phone freezes, crashes, or otherwise prevents you from resetting it via settings, alternatively you can reset the device from the Android Recovery menu which can be accessed by performing the following steps:

  1. First make sure the phone is powered off
  2. Press and hold “Volume down” and “Power” at the same time
  3. At the LG screen, quickly release and re-hold “Power
  4. At the “Factory data reset” screen release the buttons
  5. Press “Volume down” repeatedly to navigate the menu and highlight “Yes
  6. Press “Power” to confirm
  7. At the “Erase all user data and restore default settings” prompt, highlight “Yes” and press “Power” one last time

See More: LG K30: Factory Reset via Settings or Android Recovery