<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div class="w3-container w3-teal">
<h1>My Header</h1>
</div>
<img src="img_car.jpg" alt="Car">
<div class="w3-container">
<p>A car is a wheeled, self-powered motor vehicle used for transportation.</p>
</div>
<div class="w3-container w3-teal">
<p>My Footer</p>
</div>