For apps that don’t require iPad-only features, the best way to ensure that your app will work well on a Mac is to make sure it works well on iPad. In particular, your app should:

• Support multitasking. Apps that do a good job scaling the interface to support Split View, Slide Over, and Picture in Picture approach the ultimate goal of supporting the extensive window resizability that Mac users expect.
• Support drag and drop. When you support drag and drop in your iPad app, you get the same support on the Mac for free.
• Respond to keyboard shortcuts, including common macOS shortcuts. Even though a keyboard may not always be available to your iPad app, both iOS and macOS users appreciate using keyboard shortcuts to streamline their interaction with your app.