Answer:
Your answer is below, I had same questions so I know its right
Step-by-step explanation:
Changing Page Margins
Make sure the Layout tab of the ribbon (or Page Layout tab in older versions of Word) is displayed.
Click the Margins tool in the Page Setup group. ...
Click Custom Margins. ...
Adjust the top, bottom, left, and right margins as desired.
Make sure the Apply To drop-down list is set to Whole Document.
Hope it helps