The easiest way to undo in Notes on iPhone
When you open the on-screen iPhone keyboard in Notes, you’ll see several icons inside a light-gray bar at the top of it. Tap the one that looks like a pen tip inside a circle and the undo and redo icons (curved arrows) will appear at the top of your phone’s screen. The middle ground between your entire hand and one finger involves swiping across your phone or tablet screen with three fingers. Quickly drag your fingers to the left to undo, or to the right to redo. This gesture will work anywhere on the screen, but try to stay on top of the note—you risk hitting keys if you brush your fingers across the keyboard.
