Source Article: https://developer.apple.com/news/?id=06032019c
Now it’s incredibly simple to start building a native Mac app from your current iPad app. The beta version of Xcode 11 is all you need. Your Mac and iPad apps share the same project and source code, so any changes you make translate to both platforms. And your newly created Mac app runs natively, utilizing the same frameworks, resources, and even runtime environment as apps built just for Mac.