You can display the margins in Layout mode exactly as they will print. (Page margins always show in Preview mode.)
To display the page margins: In Layout mode, choose
View menu >
Page Margins. The margins show up as a thin, dotted line around the edges of the layout “page.” Page breaks appear as heavy, dashed horizontal and vertical lines.
Most printers can't print to the edge of the paper. If you place objects in the margins or outside the area the selected printer can print to, you see them in Browse and Find modes, but don't see the objects when you preview or print.