Tap on Backup & Reset (or "Reset Phone").
You will see a warning list of all data that will be removed. Confirm by tapping Reset Phone or Clear All Data . How to Hard Reset VIVO X9s
Finally, tap Erase Everything or Confirm . The phone will restart automatically and begin the wiping process. This may take a few minutes. Method 2: Hard Reset via Recovery Mode (For Locked or Frozen Phones) Use this method if you forgot your screen lock, the phone is stuck on the logo, or the screen is unresponsive. Tap on Backup & Reset (or "Reset Phone")
The phone may ask for your security password, pattern, or PIN to verify your identity. Finally, tap Erase Everything or Confirm
Select Erase All Data (Factory Reset). You might also see an option like "Reset to Factory Settings."
Scroll down and tap on More Settings (sometimes labeled "System Management" depending on your Funtouch OS version).
Open the Settings app on your VIVO X9s.