There are several ways that you can add labels to an axis in Excel 2007. This particular histogram is supposed to be depicting the number of plants that contain a certain quantity of seeds. The number of plants is represented by the column height which corresponds to the vertical axis, and the number of seeds corresponds to the horizontal axis. First, let's look at how to add an axis title to make this information clearer to viewers.
To add a horizontal axis title, make sure that your chart is selected again and return to the Layout tab on the Excel ribbon. Click on Axis Titles and then select Primary Horizontal Axis Title. For this axis, you'll only have one option other than None so we'll select Title Below Axis.
Just as with the chart title in the previous section, a default title will now appear below the horizontal axis. Click on this text to edit it.
To add a vertical axis title, we'll have more choices. Click on Axis Titles again and select Primary Vertical Axis Title. Select the format that you would like to use.
For this example, we'll use the Rotated Title option. Again, a default title will appear that you can click on and edit.
Note: To add markers to either axis, click on Axis in the Axes grouping on the Layout tab. You'll again have several options to choose from. If you want to make changes to the way the axis information is presented, refer to the tutorial on how to change axis labels in Excel 2007.