how many lock type in iOS ,what's the difference between them

In iOS, there are several types of locks that can be used to secure apps and data. The primary lock types include:

Face ID: This is a facial recognition system designed and developed by Apple for secure authentication. It uses a TrueDepth camera system to map the geometry of your face.
Touch ID: This is a fingerprint recognition feature, designed to provide secure access to your device and apps. It uses a capacitive touch sensor to read your fingerprint.
Passcode: A numeric or alphanumeric code that you can set to unlock your device and access apps. It serves as a fallback method if biometric authentication fails.

In iOS 18, Apple introduced the ability to lock and hide apps, requiring authentication via Face ID, Touch ID, or a passcode before access. This feature provides an additional layer of privacy by ensuring that sensitive information within apps is not accessible without proper authentication. When an app is locked or hidden, its contents are not visible in other parts of the system, such as search or notifications, ensuring privacy even when the device is shared with others.

For more details on this feature, you can refer to the session What’s new in privacy (19:49).