Tools
UX Pencil
Press D to activate the UX Pencil.
The UX Pencil creates freehand marker-style strokes on the current page. It works in Model Mode and Design Mode.
Draw
Press D.
Drag on the canvas.
Release to finish the stroke.
Hold Shift while drawing to create a straight stroke.
Edit strokes
Press V to return to the Select tool. Select a stroke to move or delete it. Stroke data is saved with the local document and reopened with the page.
Use Command + Z and Command + Shift + Z for supported drawing undo and redo behavior.