1. Change $config['index_page'] = "index.php" to $config['index_page'] = "" in config.php
2. Change $config['uri_protocol'] ="AUTO" to $config['uri_protocol'] = "REQUEST_URI" in config.php
3. Create .htaccess file in root dir of your application and paste the following code
RewriteEngine on
RewriteCond $1 !^(index.php|resources|robots.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]