HTML is the structure of what you see on the web. Think of it in terms of the framework of a webpage.

HTML5 is the latest and greatest iteration of HTML (Hyper Text Markup Language) and it brings a ton of great features to the table. HTML5 allows developers to build robust and more diverse websites and applications than ever before.

For a comprehensive look at all of the new features of HTML5, checkout this page over at the Mozilla Developer Network

Here's an HTML5 Boilerplate

<!DOCTYPE html>
        <meta charset="utf-8">
        <meta http-equiv="x-ua-compatible" content="ie=edge">
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        <!-- Link stylesheets here -->
        <link rel="stylesheet" type="text/css" href="style.css"> 
        <div class="container">
            <div class="title">
                <h1>Code Snippet</h1>
            <div class="content">
                <p>Hello, World!</p>
        <!-- Link script files here -->
        <script src="script.js"></script>