Sample code for post on how to hide WordPress titles - https://www.nutt.net/hide-post-titles-wordpress/

hide-title.css

.postid-123 .page-title {
  display: none;
}

hide-title.php

add_action( 'wp_head', 'hide_title' );
function hide_title() {
  if (is_single()) {
    if (metadata_exists( $post->post_type, $post->ID, 'hide_title')) {
      echo '<style type="text/css">.page-title {display:none;}</style>';
    }
  }
}