How can PHP be used to pass data in the subject line of an email using mailto?

To pass data in the subject line of an email using mailto in PHP, you can concatenate the subject line variable with the mailto link. This can be achieved by creating a PHP variable to hold the subject line value and then including that variable in the href attribute of the mailto link.

<?php
$subject = "Your Subject Here";
?>
<a href="mailto:recipient@example.com?subject=<?php echo urlencode($subject); ?>">Send Email</a>