It may be necessary to change the DirectoryIndex priority to load, for example, index.html over index.php by default.
To adjust the global Apache configuration for all users, you can log in to WHM and visit the following menu to make these changes:
Home »Service Configuration »Apache Configuration »DirectoryIndex Priority
More information on the menu can be found in our documentation here as well.
If the change should only be for a specific folder or user, this requires an edit to the .htaccess file. For example, the following code in the .htaccess file would place index.html before index.php in priority:
DirectoryIndex index.html index.php