Modify the definitions of the styles.

Right-click the style, either in the Home ribbon or in the Style task
pane (Ctrl+Alt+Shift+S), and choose Modify. In the Modify dialog,
click the Format button, choose Font, and change the font as desired.
Click Format again, choose Paragraph, and change the paragraph
spacing. Click OK. Repeat for the other headings.

Some settings will cascade from Normal through the heading styles, so
modify the styles in that order (Normal, Heading 1, Heading 2, ...).
See http://www.shaunakelly.com/word/styles/HowStylesCascade.html for
details.

--
Regards,
Jay Freedman
Microsoft Word MVP        FAQ: http://word.mvps.org
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