I think you are stuck in a "html page" mindset...
... don't worry; most of us were there in our early days of zencart :D
Dynamic content sites store "commonly used information" in a database. ie: data that is used throughout the site in a variety of situations...
... The data is "called up" and assembled into the web-page, as and when it is needed. This is an efficient system, as it means you only have to enter information ONCE, and the code then deals with how it is to be used.
Follow the advice given above if you want to change factual data about your store (name, address, emails, telephone, location, etc...)
If you want a "page" that is more along the lines of "About Us", then you can use a spare "defined page", or create an EZpage.