If you are creting your envelope by adding it to a document using the
Envelopes and Labels option or merging to a new envelope, you can either
reduce the size of the font you are using for the address, or increase the
size of the /frame/ that Word puts the address in - if you clcik in the
address, you should be able to see the frame, then grab it with the mouse
and resize it, or right-click and use the Format Frame option.

Peter Jamieson