If visiting a folder on your site shows a plain "Index of /foldername" page listing every file instead of your actual page, directory indexing is turned on and there's no index file cPanel can serve instead. Fix it in cPanel's Indexes tool (under Advanced) for that folder, or add an index.html / index.php file to the folder so it loads automatically.
Turn off indexing in cPanel
Log in to cPanel and open Indexes (under Advanced). Click through the folder tree to the directory you want to lock down, select it, and disable directory indexing. This turns off directory listing for that folder, so visitors no longer see a file list when no index file is present.
You can apply this per-folder. A common pattern is leaving your main site directory alone (it has an index.php or index.html already) and locking down subfolders that hold uploads, backups, or assets that were never meant to be browsed directly, like /images, /uploads, or /backup.
Do it manually with .htaccess
If you'd rather edit the file directly, open File Manager and navigate to the folder in question. Edit (or create) .htaccess there and add:
Options -Indexes
Save the file. If the file doesn't exist yet, dotfiles like .htaccess may not show by default in File Manager, so check its settings for an option to show hidden files.
Why this happens
Apache's default behavior, when a visitor requests a folder URL and no index.html, index.php, or similar file exists in it, is to list the folder's contents if the Indexes option is enabled. That's convenient on a dev server but a liability in production: it can expose file names, structure, and sometimes files you didn't intend to publish, like old config backups or unminified source.
The cleanest long-term fix is both: disable indexing so nothing is ever listed by accident, and make sure every public-facing folder has an index file so visitors land on real content instead.
Check your PHP settings while you're in there
If the folder in question runs a PHP application and you're also troubleshooting upload or file-size issues nearby, that's a separate setting: PHP limits like upload_max_filesize are controlled from cPanel's MultiPHP INI Editor under Software, not from Indexes.
When to contact support
If folders are still listing their contents after you disable indexing, or you're not sure which directories are safe to lock down without breaking your site, open a ticket from the portal. Support is real people, not a bot, and they can help troubleshoot further.