The number of pages in a document can be specified at document creation. After this, the Pages panel is used to add and remove pages.
The panel displays master pages in the upper Master Pages window and publication pages in the lower Pages window.
Master pages act like templates, in that a master page can be shared by multiple publication pages. A master page can contain objects of its own, such as a header or footer.
If you edit a master page at a later date, all pages to which it has been applied will update to the new design instantly, although you can override master page content and design at any time.
On the Pages panel:
On the Pages panel's Pages window:
On the Pages panel's Master Pages window:
The master page is also removed from any other master and publication pages to which it was applied.