title: PHP form doesnt output expected string
body: <p>I'm sorry for this stupid question but I'm just starting out with coding. I'm following tutorial on youtube and my code isn't doing what the mentor is showing.</p>
  
  <pre><code>&lt;?php
  
      if (isset($_POST['submit'])) {
          echo 'form is submited';
      }
  
  ?&gt;
  
  &lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
  
  &lt;head&gt;
      &lt;link rel="stylesheet" type="text/css" href="styles.css"&gt;
      &lt;title&gt;PHP OOP Tutorial&lt;/title&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
  
      &lt;div class="new-user"&gt;
          &lt;h2&gt;Create new user&lt;/h2&gt;
          &lt;form action="&lt;?php echo $_SERVER['PHP_SELF'] ?&gt;" method="POST"&gt;&lt;/form&gt;
          &lt;label&gt;Username:&lt;/label&gt;
          &lt;input type="text" name="username"&gt;
          &lt;label&gt;Email:&lt;/label&gt;
          &lt;input type="text" name="email"&gt;
          &lt;input type="submit" name="submit" value="Submit"&gt;
      &lt;/div&gt;
  
  &lt;/body&gt;
  
  &lt;/html&gt;
  </code></pre>