<?php the_title( '<h2>', '</h2>' ); ?>
<?php
// Retrieve the existing value (if any) to display in the field.
$subtitle = get_post_meta( get_the_ID(), 'wpsnipp_post_subtitle', true );

// If we have a subtitle, let's show it.
if ( $subtitle ) : ?>
  <h3><?php echo sanitize_text_field( $subtitle ); ?></h3>
<?php endif; ?>