Wordpress shortcode function: echo vs return

echo_vs_return_in_shortcodes.php

<?php

// Don't use echo in the shortcodes. If you have to, use ob_start() / return ob_get_clean()
add_shortcode('test', 'my_test_func');
function my_test_func( $args ) {
  ob_start();
  
  ?>
  your content / html / etc
  <?php

  return ob_get_clean();
}