How can the lack of a form tag with the appropriate action and method attributes impact the functionality of a PHP script that uses the post method?

Without a form tag with the appropriate action and method attributes, the PHP script will not be able to receive the form data sent using the POST method. To fix this issue, you need to ensure that the form tag includes the action attribute with the URL of the PHP script and the method attribute set to "post". This way, when the form is submitted, the data will be sent to the PHP script using the POST method.

<form action="process_form.php" method="post">
  <!-- form inputs here -->
</form>