Do you have any knowledge about Apache and Modules?
Probably you are speaking about a directory listing in Apache. Apache itself cannot show a directory listing. The most sophisticated directory listing in Apache is realized with the Apache Module "mod_autoindex". See
https://httpd.apache.org/docs/2.4/mod/m ... index.html for a full documentation including many examples.
In that mod_autoindex there are some Options which can be used at runtime, one of the most powerfull options means to apply a CSS Style Sheet for the index listing. That Option is called "IndexStyleSheet", see
https://httpd.apache.org/docs/2.4/mod/m ... stylesheetWith the help of that StyleSheet, which can applied for the index listing, you have the opportunity to apply your own background for the "body" Tag, where you can apply any background color, or an background image or whatever you like. You must have some extended knowledge about HTML and CSS in order to understand how to configure everything you need.
Last not least, of course you can use your own index.php for a directory listing. If you do so, you can do everything what you want. Feel free to write your own directory listing instead of using an Apache Module.