Press and hold the Power button
Tap Restart if it appears
If Restart does not appear, tap Power off
Wait a few seconds
Press and hold the Power button again
Release when the Vivo logo appears
If the phone is frozen, press and hold the Power button for 10 to 15 seconds until it restarts
If needed, press and hold Power and Volume Up or Volume Down together on some models, then choose Restart
If the screen is unresponsive, connect the phone to a charger and try again