<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>JavaScript</title>
  <script>
    function addElement() {
      const element = document.querySelector("section");
      element.insertAdjacentHTML("beforeend", "<p>This is a new text</p>");
    }
  </script>
</head>
<body>
  <section>
    <h1>Website</h1>
    <button type="button" onclick="addElement()">Add Content</button>
  </section>
</body>
</html>