Pages serve the purpose of input, output, and control. They are views of data or process information designed for on-screen display only. They are also user data entry vehicles.
Pages are made up of various combinations of controls, properties, actions, triggers, and C/AL code.
Controls provide the user with ways to view, enter, and edit data, choose options or commands, initiate actions, and view status
Properties are attributes or characteristics of an object that define its state, appearance, or value
Actions are menu items (which may be icons)
Triggers are predefined functions that are executed when certain actions or events occur
The internal structure of a page maps to an XML structure, some of which is readily visible in the Page Designer display while the rest is in the background.