<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>
<nav class="navbar navbar-expand-lg navbar-dark">
<a href="#" class="navbar-brand">Logo</a>
<button class="navbar-toggler" type="button" data-target="#navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse">
<ul class="navbar-nav">
<li class="nav-item active">
<a href="#" class="nav-link">Home</a>
</li>
<li class="nav-item">
<a href="#" class="nav-link">Product</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navdrop" role="button" data-toggle="dropdown" data-hover="dropdown">Services</a>
<div class="dropdown-menu" aria-labelledby="navdrop">
<a href="#" class="dropdown-item">Service1</a>
<a href="#" class="dropdown-item">Service2</a>
<a href="#" class="dropdown-item">Service3</a>
</div>
</li>
<li class="nav-item">
<a href="#" class="nav-link">Contact Us</a>
</li>
</ul>
</div>
</nav>
