<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown button
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenu">
<a class="dropdown-item" href="#">Item</a>
<a class="dropdown-item" href="#">Another item</a>
<a class="dropdown-item" href="#">One more item</a>
</div>
</div>