Margin is the distance from the edge of the page to the text. You can usually insert text and graphics in the printable area in the margins, and you can also put some items (such as headers, footers and page numbers) in the margins.

To open a word document, we first click the Page Layout option in the main menu and find the Page Setup sub-item in the submenu. Then we click the triangle symbol on the right side of the "Page Setup" sub-item and a page will pop up.

Then we found the "margins" item in the "margins" interface of the "Page Setup" dialog box. Just reset the parameters of the left and right margins.