Themes define the look of your entire document—the color scheme, the pairing of the default fonts used for body and heading text, and even the shading effects on graphics. Once you’ve selected a theme, you can use the font pairing and the color palette in your formatting to apply a unified look to your document design.
On the Page Layout tab, click the Themes button to display the Themes gallery.
Do any of the following:
Point to a theme to see how your document will look if you use that theme.
Click the theme ...