Determine what kind of numbering you want to use for your document or book. For long documents, you can assign chapter numbers. Each document can be assigned only one chapter number. If you want to use different numbering within a document, you can define ranges of pages as sections; these sections can be numbered differently. For example, the first ten pages of a document (the front matter) might use Roman numerals, and the rest of the document might use Arabic numerals.
For a video on numbering pages, see www.adobe.com/go/vid0217.
You can add a page number marker to your pages to specify where a page number sits on a page and how it will look. Because a page number marker updates automatically, the page number it displays is always correct—even as you add, remove, or rearrange pages in the document. Page number markers can be formatted and styled as text.
A single InDesign document can contain up to 9,999 pages, but page numbers can be as large as 99,999. (For example, you can correctly number a 10‑page document that starts on page 9,949.) By default, the first page is a recto (right) page numbered 1. Odd-numbered pages always appear on the right; if you use the Section Options command to change the first page number to an even number, the first page becomes a verso (left) page.
If the automatic page number is on a master page, it displays the master page prefix. On a document page, the automatic page number displays the page number. On a pasteboard, it displays PB.
By default, pages are numbered using Arabic numerals (1, 2, 3...); however, you can number pages using upper or lowercase Roman (i, ii, iii...) or alphanumeric (a, b, c...) numbering.
You can add a chapter number variable to your document. Like page numbers, chapter numbers can be updated automatically and formatted and styled as text. A chapter number variable is commonly used in documents that are part of a book. A document can have only one chapter number assigned to it; if you want to divide a single document into chapters, you can create sections instead.
You can update starting number and format of chapter numbering by choosing Layout > Numbering & Section Options.