Just like publication pages, master pages can be a single page or two-page spread equally, and can be applied to equivalent publication pages or spreads.
At initial document setup, if Default master is selected, a master page will be created and applied to publication pages created at this time. After this, you can create and apply master pages at any time using the Pages panel.
Master pages can be applied to other master pages in more complex documents. For example, a 'parent' master page containing just page numbering could be applied to multiple 'child' master pages colored separately for each section. This means you only need to change the page number style on the parent master page; also, as you create new pages you only need assign a child master page, which will inherit page numbering automatically from its parent.
On a publication page, an applied master page is actually a layer that is indicated on the Layers panel by a vertical solid turquoise marker on the master layer's thumbnail. The layer can be expanded to expose the inherited master page's elements within, with vertical solid turquoise markers on their thumbnails.
Any master page elements edited on your publication page will show dotted turquoise markers on their layer entry.
By dragging a master layer to the top of the layer stack, you can present master page items in front of all other items in your publication.
By selecting the master page's layer on the Layers panel, the inherited content can be collectively transformed. Individual objects cannot be selected on the panel and then transformed, unless you detach the master page. The content of text objects and picture frames can be edited, though.
To prevent inadvertent transformation or editing of inherited content (other than text/picture frame content), select and then lock the master layer on the Layers panel.
With a master layer selected on the Layers panel, you can manage the master's destination (whether it is applied to the left/top, right/bottom, or both pages; available only for documents with facing pages), scaling behavior and anchor position by tapping Layer Options. The relevant settings are shown in the Master Placement section.
The following scaling behaviors are available:
On the Pages panel:
If the current spread contains facing pages, the master is applied to both of them.
On the Pages panel:
Do one of the following: