The LG device supports three sound profiles such as Sound, Vibrate Only and Silent, and the sound profile can be changed using the normal settings, quick settings or the volume buttons.

Android 9 | LG UX 9.0
Change sound profile -  Open the  Settings
Change sound profile -  Tap on  Sound
Change sound profile -  Tap on  Sound profile
Change sound profile -  Choose between  Sound ,  Vibrate only  and  Silent
  1. Open the Settings
  2. Tap on Sound
  3. Tap on Sound profile
  4. Choose between SoundVibrate only and Silent

LG Instructions