You can easily add various geometric shapes and arrows to any PDF file. Here is how.
1. Click Comment.
2. On the toolbar, choose a shape - Line, Rectangle or Ellipse.
3. Click where you want to position the shape and resize it using the dragging points.
Alternatively:
1. Select a shape.
2. Left-click it, then hold and drag your mouse to draw the shape.
Optionally, you can also draw a custom shape with the Free Draw instrument.