Click on the Format button and the click on Format Cells (Figure 1).

Figure 1

Click on the Alignment Tab.
Check the box to Wrap Text and click OK (Figure 2).

Figure 2

NOTE: Data in the cell will wrap to fit the column width. When you change column width, data wrapping will adjust automatically.

NOTE: If all wrapped text is not visible, it may be because the row is set to a specific height. To allow the row to adjust automatically and show all wrapped text, point to row on the format menu, and then click AutoFit.