1. Go to Layout > Margins.
2. Select Custom Margins.
3. In the Gutter box, enter a width for the gutter margin.
4. In the Gutter position box, click Left or Top. Note: The Gutter position box is not available and determined automatically when you use the Mirror margins, 2 pages per sheet, or Book fold option.

A gutter margin adds extra space to the side, top margin, or inside margins of a document you plan to bind. That helps ensure that text isn’t obscured by the binding.

Margin that is added to the binding side of the page when printing. Key Points. A gutter margin enlarges the top, inside, and side margins of a document that you intend to bind. A gutter margin ensures that the binding won’t cover the text.

A gutter margin extends the side, top or inside margins of a document that you intend to bind. This helps to ensure that the binding does not obscure the text.