<meta>

This tag is used to provide metadata on the HTML document. Metadata aren't visible on the page and can be used by browsers to tell, for example, how to display the content of a page. They allow, among other things, to take control of the viewport (the visible part of a page), to specify the type of encoding special characters, to allow a responsive behavior on some nomadic media… <meta> are always written in the <head> tag.

<!DOCTYPE HTML>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>

<body>
</body>
</html>

A question?