How to create a footer in CSS
Unfortunately it is impossible to create a footer by means of CSS only. CSS can only be used to format the footer because the actual footer basic structure will be an HTML structure. As soon as the various required elements have been created in HTML, they can be called up by the CSS and they can be assigned for example a height or a background color.
Extra:
How to create a sticky footer at the bottom of your screen is a frequently asked question. The answer to that question can be found here: How to create a sticky footer in CSS