In Apache, we can add the description of file by adding the following(similar) in file /etc/apache2/mods-available:
AddDescription "your message" filepath with respect to your shared directory
But how can we set the font color of the "your message" in description. For example take a look of following image:

I want the text under rectangular region with font color red. How can we do this ?
                        
You can do this by adding HTML message with the apache AddDescription directive. Quote from the apache documentation:
Example:
This should work in apache 2.2 and 2.4. To read more about the mod_autoindex visit the apache docs: http://httpd.apache.org/docs/current/mod/mod_autoindex.html#adddescription