how to add background color to shapes in swiftui code example

Example 1: how to put background image in swiftui

var body: some View {
    TabbedView(selection: $selection, content: {
        VStack {
            Text("TEST 0")
                .background(Color.clear)
            }
            .tabItemLabel(Text("Simple Center"))
            .tag(0)
        VStack {
            Text("TEST 1")
                .background(Color.clear)
            }
            .tabItemLabel(Text("Bottom Right"))
            .tag(1)
            .background(Color.clear)
        VStack {
            Text("TEST 2")
                .background(Color.clear)
            }
            .tabItemLabel(Text("Rotator"))
            .tag(2)
        VStack {
            Text("TEST 3")
                .background(Color.clear)
            }
            .tabItemLabel(Text("Quadrants"))
            .tag(3)
            .background(Color.clear)
    })
    .background(
        Image("background-gradient")
            .resizable()
            .scaledToFill()
    )
    .padding()
}

Example 2: shapes in swiftui

struct ContentView: View {
    var body: some View {
        ZStack {
            Rectangle()
                .fill(Color.black)
                .frame(width: 200, height: 200)

            RoundedRectangle(cornerRadius: 25, style: .continuous)
                .fill(Color.red)
                .frame(width: 200, height: 200)

            Capsule()
                .fill(Color.green)
                .frame(width: 100, height: 50)

            Ellipse()
                .fill(Color.blue)
                .frame(width: 100, height: 50)

            Circle()
                .fill(Color.white)
                .frame(width: 100, height: 50)
        }
    }
}