Graphical notes can be deleted using the Comments catalogue which will also remove them from the document.

Alternatively:

  1. Select the Hand tool on the Edit toolbar or any graphical tool on the Commenting toolbar (View > Toolbars > Commenting).
  2. Click on the outline of the shape to be deleted.
  3. Press Backspace or Delete on the keyboard. Alternatively, right-click on the outline and choose Delete.