Excel is not a word processor, so it doesn't provide a rich set of text
formatting options the way a word processor would. There is line spacing
options beyond those listed in the Vertical drop down box on the Alignment
tab on the Format/Cells dialog box. If all the text is always visible,
perhaps setting the height of the row to show more than the text's height
and using the Distributed item in the Vertical Alignment drop down will do
as an alternative.