step 1: create .htaccess file under root directory
step 2: on .htaccess file add this
RewriteEngine on
RewriteCond $1 !^(index.php|resources|robots.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]
step 3: on config file change this $config['index_page'] = 'index_page';
to $config['index_page'] = '';