To enable this feature follow these steps:

1. Login to WHM as root.
2. Go to Tweak Security.
3. Click the 'mod_userdir' Configure button and enable it.

To disable this feature follow these steps:

1. Disable the mod_userdir via WHM as per the above steps. If that does not work, read on.
2. Login to ssh as root and open up httpd.conf file.
3. Search for mod_userdir.c and comment out the following line as shown below:
    # AddModule mod_userdir.c
4. Run a second search for mod_userdir.c and comment out the following lines as shown below:
    <IfModule mod_userdir.c>
    UserDir public_html
    </IfModule>
5. Restart apache: /etc/init.d/httpd restart