JAMIN

The following code will disable commenting and trackback features of WordPress. You can completely turn off the comment feature by the following code.

But if your theme has “This post has x comments” feature this code won’t stop showing the message. For that you have to fix it by removing the code from your design.

Simply open your function.php.
If you don’t know where the file is, go to your dashboard. In Appearance menu click on “theme File Editor” If you get any warnings click on ” Understand” and go to Theme Functions (functions.php). At the end of the file paste the following code.

/*disable comment*/// First, this will disable support for comments and trackbacks in post types
function df_disable_comments_post_types_support() {
   $post_types = get_post_types();
   foreach ($post_types as $post_type) {
      if(post_type_supports($post_type, 'comments')) {
         remove_post_type_support($post_type, 'comments');
         remove_post_type_support($post_type, 'trackbacks');
      }
   }
}

//wordpress-code-completely-disable-comments-using-functions-php

add_action('admin_init', 'df_disable_comments_post_types_support');

// Then close any comments open comments on the front-end just in case
function df_disable_comments_status() {
   return false;
}
add_filter('comments_open', 'df_disable_comments_status', 20, 2);
add_filter('pings_open', 'df_disable_comments_status', 20, 2);

// Finally, hide any existing comments that are on the site. 
function df_disable_comments_hide_existing_comments($comments) {
   $comments = array();
   return $comments;
}
add_filter('comments_array', 'df_disable_comments_hide_existing_comments', 10, 2);

/*disble comment end*/