Every HTML5 document begins with a <!DOCTYPE html>
declaration to ensure standards-compliant rendering. Here's the basic skeleton of an HTML5 document:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document Title</title>
</head>
<body>
<!-- Content goes here -->
</body>
</html>