Using W3.CSS
A great way to create a responsive design, is to use a responsive style sheet, like W3.CSS.
W3.CSS makes it easy to develop sites that look nice at any size; desktop, laptop, tablet, or phone.
EXAMPLE:
<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<body>
<div class="w3-container w3-green">
<h1>W3Schools Demo</h1>
<p>Resize this responsive page!</p>
</div>
<div class="w3-row-padding">
<div class="w3-third">
<h2>London</h2>
<p>London is the capital city of England.</p>
<p>It is the most populous city in the United Kingdom,
with a metropolitan area of over 13 million inhabitants.</p>
</div>
<div class="w3-third">
<h2>Paris</h2>
<p>Paris is the capital of France.</p>
<p>The Paris area is one of the largest population centers in Europe,
with more than 12 million inhabitants.</p>
</div>
<div class="w3-third">
<h2>Tokyo</h2>
<p>Tokyo is the capital of Japan.</p>
<p>It is the center of the Greater Tokyo Area,
and the most populous metropolitan area in the world.</p>
</div>
</div>
</body>
</html>
Bootstrap
Another popular framework is Bootstrap, it uses HTML, CSS and jQuery to make responsive web pages.
EXAMPLE:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<div class="jumbotron">
<h1>My First Bootstrap Page</h1>
</div>
<div class="row">
<div class="col-sm-4">
...
</div>
<div class="col-sm-4">
...
</div>
<div class="col-sm-4">
...
</div>
</div>
</div>
</body>
</html>