This article is just a quick reference not a duplication of Microsoft’s work. For more details about checkboxes please visit :
"On the View menu, point to Toolbars, and then click Forms. On the Forms toolbar, click Check Box Form Field . Note If the check box has a gray background, click Form Field Shading on the Forms toolbar to remove the gray shading. Click the next cell where you want to insert a check box, and then press CTRL+Y to insert another check box. After you insert a check box for each item that you want, click the top right cell and type the text for the first item. Repeat this step for each item in the list."