1. Enter reading page -> Tools;
2. Select Freehand on the toolbar;
3. There you can change the Color and Line Width on the side panel;
4. And a eraser is available to erase the undesired annotations, a ruler and a protractor are provided if you need to draw a line or a circle;
5. Click Done when you finish your freehand drawing;
6. To remove the annotation, right click the annotation and select Delete.