What are the potential pitfalls of not properly structuring PHP and HTML code for search engine visibility?

Improperly structuring PHP and HTML code can lead to search engines having difficulty crawling and indexing your website's content, resulting in lower visibility in search engine results. To ensure better search engine visibility, it is important to properly structure your code by using semantic HTML tags, optimizing meta tags, and implementing clean URLs.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="description" content="Your website description here">
    <meta name="keywords" content="keywords, here">
    <meta name="author" content="Your Name">
    <title>Your Website Title</title>
</head>
<body>
    <header>
        <h1>Your Website Header</h1>
    </header>
    <nav>
        <ul>
            <li><a href="/">Home</a></li>
            <li><a href="/about">About</a></li>
            <li><a href="/services">Services</a></li>
            <li><a href="/contact">Contact</a></li>
        </ul>
    </nav>
    <section>
        <h2>Main Content Section</h2>
        <p>Your content goes here.</p>
    </section>
    <footer>
        <p>© <?php echo date("Y"); ?> Your Website Footer</p>
    </footer>
</body>
</html>