<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>
<body style="background: #333;">
<div class="container">
<div class="row" style="margin-top:50px;">
<div class="col-md-4 mx-auto col-12">
<div class="b-select-wrap">
<select class="form-control b-select">
<option>Gender</option>
<option>Male</option>
<option>Female</option>
</select>
</div>
</div>
<div class="col-md-4 mx-auto col-12">
<div class="b-select-wrap">
<input class="form-control b-select" type="text" name="" placeholder="WaLia">
</div>
</div>
</div>
</div>
</body>