This widget is used in account-based storefronts. It provides the shopper with the ability to look up and select shipping addresses saved for the account they are associated with; see the Create Page Layouts that Support Different Types of Shoppers chapter for more details.
In order to use this widget, a vertical tab stack must be created with the Managed Account Address Book widget placed on a tab that is accessible to approvers only.
It is available for the page types within the Checkout layout.