Issue
Is it a pre-designed page or generated? Note, I am talking about the page you see when a directory is listed, not the default Apache page.
Solution
When no valid DirectoryIndex file is found, Apache will generate the "Index of /" page dynamically. You can customise it to an extent with mod_autoindex, but it's not particularly straightforward.
For basic customisation, take a look at Perishable Presses Better Default Directory Views with HTAccess. From the article:
While there are many scripts available to customize the appearance and functionality of default directory navigation, most of these methods are either too complicated, too invasive, or otherwise insufficient for expedient directory styling. In this comprehensive tutorial, you will learn how to use the built-in functionality of Apache's
mod_autoindexmodule to style and enhance your default directory views with a smorgasbord of stylistic and functional improvements.
The article is about 13 years old, but the methods outlined continue to work with modern versions of Apache.
Answered By - matigo Answer Checked By - Senaida (WPSolving Volunteer)