Facing pages (also known as a two-page spread) are often used for book layouts and for double-sided documents that you intend to print. Documents that use facing pages can have different headers, footers, and master objects on left- and right-facing pages.
Before you begin, determine whether you're working in a page layout or word-processing document. Documents are either one or the other, and you set up facing pages differently for each.
Click 
in the toolbar, then click the Document tab at the top of the sidebar.
Select the Facing Pages checkbox.
In page thumbnail view, the page thumbnails rearrange as two-page spreads. If your document zoom is set to Two Pages, left and right pages appear side-by-side in the Pages window.
To set top, bottom, inside, and outside margins, do one of the following:
In a page layout document: In the Header & Footer Margins section of the Document sidebar, click the arrows or enter values in the fields. (In page layout documents, you set header and footer margins, not page margins.)
In a word-processing document: In the Document Margins section of the Document sidebar, click the arrows or enter values in the fields.
The inside margin is the side of any page that goes into the binding. The outside margin is on the outside edge of each page.
To use different headers and footers for left- and right-facing pages, do one of the following:
In a page layout document: Select the “Left and right pages are different” checkbox below the Facing Pages checkbox.
In a word-processing document: Click the Section tab at the top of the Document sidebar, then in the Headers & Footers section, select the “Left and right pages are different” checkbox. If your document has more than one section, you may need to do this for each section.
To learn how to edit headers and footers, see Add headers and footers.