Productivity · Free
SidePane
Unfold a second screen for your Mac, with touch and Apple Pencil.
SidePane turns iPhone Duo into an extended display for your Mac, over the cable or Wi-Fi, with touch and Apple Pencil support. The Mac display follows whichever screen you use, inner or cover, and resizes when you fold or rotate. Stand it up in tent mode to sign a document with Apple Pencil, or unfold it for room to show a whole reference page.
SidePane is free to download, with 15-minute sessions as often as you like. A one-time $9.99 purchase unlocks it, with no subscription and no account.
Details and FAQ