The URLs are automatically constructed by APEX, so in most cases we do not need to understand the syntax nor modify it. On the other hand, understanding how URL (f?p) syntax works can be useful while defining hypertext links to the pages.
Let’s take a look at the parameters send as variable “p”:
App: Uniquely identified application ID
Page: Unique page ID
Session: Randomly generated session ID – to keep your session information.
Request: The value of REQUEST. When you click a button, the value of REQUEST will keep the name of the button. Bind variable: :REQUEST
Debug: DEBUG flag. Setting this flag to YES displays details about application processing.
ClearCache: Clears the cache if you specify he numeric page number.
ItemNames: Comma-delimited list of item names (stored in user’s session).
ItemValues: List of item values (stored in user’s session)
PrinterFriendly: If it’s set to YES, the page is rendered in printer friendly mode.