You may need to quickly turn off biometric authentication on your iPhone. Instead of delving into the settings, this quick shortcut temporarily disables Face or Touch ID on your iPhone.
If you’re somewhere (like a border control or a party) where you think your face or thumbprint could be used against your will to unlock your iPhone, this quick shortcut will turn off biometric authentication. You can even do it if your iPhone is in your pocket.
On your iPhone, simply press and hold the Volume Up and Side buttons (the Sleep / Wake button on older iPhones) for a second or two.
When you see the “Slide to Power Off” menu or feel a vibration, it means that biometric authentication has been disabled.
You don’t need to turn off your iPhone; press the side / power button again to lock it. From now on, your iPhone will not unlock without your password.