To quickly add Annotations to the Chart use the icons found on the top left-hand side of the Chart Window. You will find icons for a Horizontal Line, a Trend Line, an Arrow, and Text Annotation there. To place an Annotation on your chart, click on one of these icons, then move your mouse to the desired location on the Chart. Click into the Chart to add the Annotation. You can change the Annotation position via drag and drop, you can change the size or direction of Trend Lines and Arrows via grab and drag.
To quickly change the color of any Chart Annotation, select it on the Chart, then click Color Changer Icon and make a color selection. To remove an Annotation, simply select it on your Chart, then press the Delete key on your keyboard.