To Create Custom Margins:

• Choose Page Layout tab on the Ribbon.  Under Page Layout, choose Margins.  A Margin Gallery will appear.
• Choose Custom Margins on bottom of the Margin Gallery.  A Page Setup dialog box will appear.
• Use the spin arrows  to increase/ decrease your margin settings for the top, bottom, left, and/or right margins of your document.  You may also type your exact margin measurements in the box.
• Apply these measurements to the entire document or from this starting point.
• Choose OK to apply the margin settings to your document.