<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>
<div class="container">
<h1>Custom Checkboxes</h1></br>
<label class="customcheck">One
<input type="checkbox" checked="checked">
<span class="checkmark"></span>
</label>
<label class="customcheck">Two
<input type="checkbox">
<span class="checkmark"></span>
</label>
<label class="customcheck">Three
<input type="checkbox">
<span class="checkmark"></span>
</label>
<label class="customcheck">Four
<input type="checkbox">
<span class="checkmark"></span>
</label>
</div>
