A multi-page consists of one or more pages. Each page contains a set of controls and can have their own layout. A common example is a longer form which is broken down into several pages, e.g. an e-commerce checkout where one page consist of confirmation of the checkout cart, another of the card information, another of the delivery address. Another example are sign-up forms for newsletters where the user first chooses a sign-in name and password, the next page is a selection of topics the user wants to get feed from.
Always use a progress bar to show how far the user has come and what is left to do. It should also have sign-posting to show more specifically at what step the user is.
Also called multi-step form.