iOS 12 at a quick glance.

iOS 12 - A quick look

ARKit 2: Multiuser and Persistent AR. Use world-mapping data to bring your app’s users together in shared AR experiences, and store data from an AR session in your app so it’s easy to revisit it later.

Siri Shortcuts: Siri can predict shortcuts to actions that a user may want to perform using your app, and suggest those shortcuts to the user in places such as Spotlight search, Lock Screen, and Siri Watch Face.

Health Records: HealthKit in iOS 12 lets users share their medical history with your app. With their permission, you can personalize health experiences based on health record data such as conditions, labs, medications, vitals, and more.

Effects: Stickers from your Sticker Packs and images from iMessage apps can now appear as effects.

Interactive Controls in Notifications: Notification content app extensions now support user interactivity in custom views. If the content of your app’s notifications needs to prompt user interaction, add controls like buttons and switches.

Authentication Services: The new AuthenticationServices framework lets you integrate password manager apps with Password AutoFill.

CarPlay for Navigation Apps: CarPlay now supports third-party navigation apps, giving drivers even more choices for a familiar experience on the dash while they drive.

More Details for end user
https://www.apple.com/in/ios/ios-12/features/