You can sign a PDF on your Mac using the giant MacBook trackpad, and you can mark up PDFs and screenshots, too. But all that stuff is much easier on the iPad, especially if you have an Apple Pencil.

Continuity Sketch and Markup are two new Sidecar-related features that allow you remotely draw graphics or annotate documents from any iPad or iPhone capable of running iPadOS 13 or iOS 13, along with ...