How can the issue of missing form tags in HTML affect the functionality of PHP scripts for form submissions?

When form tags are missing in HTML, PHP scripts for form submissions may not be able to properly identify and process the form data. To solve this issue, ensure that all form elements are enclosed within <form> tags with appropriate action and method attributes specified.

&lt;form action=&quot;process_form.php&quot; method=&quot;post&quot;&gt;
  &lt;input type=&quot;text&quot; name=&quot;username&quot;&gt;
  &lt;input type=&quot;password&quot; name=&quot;password&quot;&gt;
  &lt;button type=&quot;submit&quot;&gt;Submit&lt;/button&gt;
&lt;/form&gt;