Tap Eraser on the toolbar, then tap it again to open its options.
- Whole removes the entire stroke you touch. Partial erases only where the eraser passes, like a real eraser. Whole is the default.
- Size sets the eraser width, from 1 to 70.
- Auto switch back to last tool gives you back your pen or highlighter as soon as you lift the eraser.
- Scribble out to erase lets you scribble over writing with a pen or the pencil to erase it, without picking up the eraser.
With Apple Pencil Pro or Apple Pencil 2, in a note, set Menu › Gestures › Apple Pencil Double Tap to Switch Tool, and a double tap jumps between your pen and the eraser.