Technically a WebPage contains text and specific HTML and CSS commands which specify all the grafical and colorful elements of WebPages.

WebPages are requested by the user (browser) by their internet address (URL, e. g. http://www.google.com) and are transferred by using the http and https protocolls (which you can see as the first part of the internet address).

A special kind of WebPages are the WikiPages. They are not statically stored like normal WebPages and in the form that the user sees, but instead they are dynamically created from their parts on demand. That's the reason why they are simple to change.