You add various titles to a chart to help indicate what the chart is all about. You can add a chart title that appears at the top of the chart, and you can add axis titles that appear along the X and Y axes. Here's how you add titles and labels to a chart:
Click the Titles tab if it is not already displayed.
Enter the title you want in the Chart Title text box.
If you want titles for the X, Y, and/or Z axes, enter them in the appropriate text boxes (X, Y, or Z).
Click OK. Microsoft Graph returns you to the chart window with your new titles in place.