SwiftUI replaces the older UI Builder paradigm with a new declarative development method. This new approach brings a lot to the table, and you can discover more about it here.
SwiftUI is a fairly recent framework introduced by Apple to build UIs for iOS & more.
Discover SwiftUI, the cross-platform framework used for creating user interfaces for iOS, macOS, watchOS, and tvOs.
SwiftUI enables developers to write less code while seeing the consequences of their changes in real time, and in turn improves developer experience.
Apple not only created the framework, but they also provide a lot of great resources to get started with SwiftUI. If you are looking to work with this technology, this is a great place to learn.
Creating and Combining Views with SwiftUI Working with UI Controls Using SwiftUI to Build Lists and Navigation Drawing Paths and Shapes Animating Views and Transitions Present your app’s content in widgets with SwiftUI views. Composing Complex Interfaces UIKit x SwiftUI Handling User Input