Вы можете использовать строки и столбцы bootstrap, например, col-xs-4. Или вы можете использовать ширину 33,33% для всех полей со стилем float слева, если вы хотите сделать это, используя только CSS. Я упомянул оба решения: одно с bootstrap и одно с css.
.box {
border: 1px solid black;
background-color: grey;
color: white;
padding: 15px;
}
.my-container {
margin-left: 20%;
margin-right: 20%;
}
.my-box {
width: 33.33%;
float: left;
}
}
<!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/3.4.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container mt15">
<h3>using bootstrap 3</h3>
<div class="row">
<div class="col-xs-4 box">
<h3>Column 1</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="col-xs-4 box">
<h3>Column 2</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="col-xs-4 box">
<h3>Column 3</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="col-xs-4 box">
<h3>Column 2</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="col-xs-4 box">
<h3>Column 3</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
</div>
</div>
<div class="my-container">
<h3>Using Css only</h3>
<div class="box my-box">
<h3>Column 1</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="box my-box">
<h3>Column 2</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="box my-box">
<h3>Column 3</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="box my-box">
<h3>Column 4</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
<div class="box my-box">
<h3>Column 5</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit...</p>
<p>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris...</p>
</div>
</div>
</body>
</html>