HTML Documents: Omitting <html>, <head> and <body> 

//the following code will validate as HTML5

<!DOCTYPE html>
<title>Page Title</title>

<h1>This is a heading</h1>
<p>This is a paragraph.</p>

According to the HTML5 standard; the <html>, the <body>, and the <head> tag can be omitted.

Related concepts

→
Omitting <html>, <head> and <body>

HTML Documents: Omitting <html>, <head> and <body> — Structure map

Clickable & Draggable!

HTML Documents: Omitting <html>, <head> and <body> — Related pages:

Head