wordpress get featured image url by id code example

Example 1: get featured image url

echo get_the_post_thumbnail_url();

Example 2: get featured image post wordpress by post id

<?php if (has_post_thumbnail( $post->ID ) ): ?>
  <?php $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' ); ?>
  <div id="custom-bg" style="background-image: url('<?php echo $image[0]; ?>')">

  </div>
<?php endif; ?>