How to hide the title bar in a SwiftUI macOS app?

Let’s say you have a view named ContentView and your main App file looks like this:

@main
struct ExampleApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

To hide the title bar in the main window, you can simply add this line .windowStyle(.hiddenTitleBar) to the WindowGroup like this:

@main
struct ForegroundApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .windowStyle(.hiddenTitleBar)
    }
}

Note: Sometimes the Xcode preview doesn’t hide the title bar even after applying the above code. However, building and running the project will hide the title bar as expected.