In Word you just continue typing and the text wraps in the cell as it would
anywhere else. You can insert a line break with Shift+Enter or a paragraph
break with Enter just as you would in ordinary text. If the row height is
set to an exact amount, however, your text may not fit.
If you're actually talking about Excel, you can insert a line break with
Alt+Enter (but Excel can also wrap text if you format the cell accordingly).
--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org