How to: Add an arrow to a chart.
Solution:
Select the chart and choose 'Arrow' from 'Drawing' toolbar.
NOTE: The following procedure assumes that the 'Drawing' toolbar is displayed.
1) Double-click the desired chart. (A striped border with handles appears around the chart.)
NOTE: If the chart is on a separate chart sheet in Excel, click the tab for the chart sheet.
2) Click 'Arrow' toolbar button from the 'Drawing' toolbar. (The pointer changes to a crosshair.)
Arrow button
3) Place the crosshair where the arrow should start.
4) Press and hold down the mouse button.
5) Drag to draw the arrow on the chart.
6) Release the mouse button when the desired length is reached.