Answer: SwiftUI animates changes by watching state. You trigger animations by wrapping state changes in withAnimation {} or by attaching .animation() modifiers.

Code Example:

struct AnimatedView: View {
    @State private var isExpanded = false

    var body: some View {
        VStack {
            Button("Toggle") {
                withAnimation(.spring(duration: 0.4)) {
                    isExpanded.toggle()
                }
            }

            if isExpanded {
                Text("Expanded content")
                    .transition(.move(edge: .top).combined(with: .opacity))
            }
        }
    }
}

// Animating between two views with matchedGeometryEffect
@Namespace private var animation

// Source view
Image("thumbnail")
    .matchedGeometryEffect(id: "image", in: animation)

// Destination view
Image("thumbnail")
    .matchedGeometryEffect(id: "image", in: animation)