Face ID uses exclusive technology to create a map of your face that can then be used to unlock your iPhone or verify your identity for services (e.g., Apple Pay) or apps (e.g., My Verizon).
The steps below apply to the following models:
iPhone XS / XS Max / XR
For Touch ID settings for previous iPhone models, view this info.
From the Home screen, navigate: Settings > Face ID & Passcode.
Enter your passcode.
In the 'Use Face ID for' section, tap any of the following to turn on or off :
iTunes & App Store
Tap the Require Attention for Face ID switch to turn on or off.
Tap the Attention Aware Features switch to turn on or off.
When this featute is enabled and you're looking at the iPhone, it lowers the volume sound of your alerts. Check out the Apple Article - About Attention Aware for more info.