I would want to put information on my web page that is not visible to the typical viewer because I need to add the head of the web page to make it work. The head contains information that is not meant to show up on the visible page, but may affect it.
Metadata is information necessary to web browsers using the page because it tells the web browsers how to display the page. This metadata is needed to specify which character set is used, page description, and author. The metadata viewport tag tells gives the browser instructions on how to control the page's dimensions and scaling.