The phone will reboot. Do not press any buttons during the installation (takes 5–10 minutes).
Locate the firmware .zip file you downloaded and tap it. How to Update Software on VIVO iQOO Z9 Turbo
Move the downloaded file to the root directory of your phone’s internal storage (do not put it inside any folder). The phone will reboot
Select Local Update or Install from storage . How to Update Software on VIVO iQOO Z9 Turbo