Hi,
Right click on the cell you want, then choose Format cells. Choose the
Alignment tab, then tick the Wrap text tick box.
This will give you multiple lines in your cell, but you won't have much
control over where each line starts and finishes. To control this, when you
type some text, then want to start a new line within the same cell, press
Alt+Enter.
Hope this helps.
Regards - Dave.