<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>
<!------ Include the above in your HEAD tag ---------->
<form>
<div class="form-group">
<label>Date Of Birth</label>
<input type="text" id="datepicker" class="form-control" placeholder="Choose">
</div>
</form>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>