1. Open your Excel document and click on a chart to edit it.
2. Click the 'Layout' tab on the Microsoft Office Ribbon at the top of the Excel window.
3. Click the 'Axis Titles' drop-down menu on the Layout tab, then select 'Primary Horizontal Axis Title' or 'Primary Vertical Axis Title' and click on a display option. For example, click 'Horizontal Title' to display the axis title horizontally.
4. Type a name for the axis in the 'Axis Title' text box and press 'Enter.'