Do any of the following:
Automatically hyphenate all of a document
On the Tools menu, point to Language, and then click Hyphenation.
Select the Automatically hyphenate document check box.
In the Hyphenation zone box, enter the amount of space to leave between the end of the last word in a line and the right margin.
To reduce the number of hyphens, make the hyphenation zone wider. To reduce the raggedness of the right margin, make the hyphenation zone narrower.
In the Limit consecutive hyphens to box, enter the number of consecutive lines that can be hyphenated.