LG Stylo 2 Plus LG-K550 - Manual (Page 26)

Basics 25
Turning Your Phone On and Off
Turning your phone on
Press and hold the Power/Lock Key on the back of the phone for a
couple of seconds until the screen turns on.
Turning your phone off
1 Press and hold the Power/Lock Key on the back of the phone until the
Phone options menu appears.
2 Tap Power off in the Phone options menu.
3 Tap POWER OFF to confirm that you want to turn off the phone.