<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/css/select2.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/js/select2.min.js"></script>
<div class="container">
<div class="row">
<form class="col-md-4">
<label>Select</label>
<select class="form-control select2">
<option>Select</option>
<option>Car</option>
<option>Bike</option>
<option>Scooter</option>
<option>Cycle</option>
<option>Horse</option>
</select>
</form>
</div>
</div>
<script>
$('.select2').select2();
</script>
