If some of the category names aren't visible along the horizontal axis of your chart, try the following:
Click the chart, and then drag one of the sizing handles to enlarge the chart. By default, the fonts in the chart scale proportionally as you resize the chart.
Click the axis, click the arrow next to Font Size , and then click a smaller font size.
Double-click the axis labels, and then change the rotation angle on the Alignment tab. If the angle is 0, 90, or – 90 degrees, the text will wrap.