How to make use of it:

1. Include the required Bootstrap 4 framework on the web page.

<link rel="stylesheet" href="/path/to/cdn/bootstrap.min.css" />
<script src="/path/to/cdn/jquery.slim.min.js"></script>
<script src="/path/to/cdn/bootstrap.min.js"></script>

Create your <select> using the .selectpicker class.

<select class="selectpicker">
  <option>Mustard</option>
  <option>Ketchup</option>
  <option>Barbecue</option>
</select>

If you’re on 1.6.3 or later, you don’t need to do anything else, the data-API automatically grabs <select> s with the selectpicker class.

// To style only <select>s with the selectpicker class
$('.selectpicker').selectpicker();

If you’re on an older version, you’ll need to add the following either at the bottom of the page (after the last selection picker) or in the $(document).ready() block.

// To style all <select>s
$('select').selectpicker();

See Demo And Download