App locker for iPhone
The said functionality is neither built into iOS natively (unlike some Android phones), nor is it available via any 3rd party apps.

However, certain apps which deal with sensitive content give you the ability to restrict access partially or totally via Touch ID/Face ID authentication. Common examples include banking, financial data management, password manager apps etc.

Partial restriction entails requiring successful authentication when accessing sensitive parts of an app (such as when authorizing a purchase on the App Store). Total restriction entail requiring successful authentication every time when accessing the app (accessing a password manager app).

Total restriction is very similar functionally to app locker feature offered in some Android devices either natively or via a 3rd party app.

To learn more about Touch ID and Face ID, refer to these links:


Use Touch ID on iPhone and iPad
Use Face ID on your iPhone or iPad Pro


A good number of built-in and 3rd party app support Touch ID/Face ID authentication. You can also search for apps catering to specific required feature (hiding sensitive photos, videos, notes) with support for Touch ID/Face ID authentication to access content.

Look for Touch ID/Face ID support in an app when going through its description or settings. Apple's Notes app for example lets your lock certain notes with Touch ID. 1Password - Password Manager for iOS offers total restriction and asks for authentication every time you try to access the app (very similar to app locker functionality).