• Login to your CPanel
• Click on Index Manager
• Directory will be list down. Click on the directory name which you want to disable the directory browsing
• Select No Index and click Save
• The directory browsing feature should be disable by now

Once you disable directory browsing, visitor will not able to browse your directory by accessing the directorydirectly (if there is no index.html file). This will protect your files from exposing to the public.