how to remove index.php in codeigniter

RewriteEngine on
RewriteCond $1 !^(index\.php|resources|robots\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA] 

//find the below code   
$config['index_page'] = "index.php" 
//replace with the below code
$config['index_page'] = ""

# Only for Nginx server
location / {
    try_files $uri $uri/ /index.php$is_args$args;
}