The gutters in a page layout separate elements from one another. Without enough space between text columns or content, elements will run together and become difficult to see or read.
When you work in Adobe InDesign, you can use the gutters to control the layout of your page and create a more consistent and visually pleasing design.
You can set the gutter size from the New Document menu when creating a new InDesign project.
Or you can update or add a gutter to an existing project by selecting Layout > Margins and Columns from the top menu bar.
For the gutter(s) to appear you will need to set the number of columns to two or more, since the gutter is the vertical space between your columns. This means that with two columns you will have one gutter visible between them. With three columns, you will have two gutters. And so on.