library btn dopdown
HTML
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown">
My account
<span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li><a class="dropdown-item" href="#">My cart</a></li>
<li><a class="dropdown-item" href="#">My orders</a></li>
<li><a class="dropdown-item" href="#">My details</a></li>
<li role="separator" class="dropdown-divider"></li>
<li><a class="dropdown-item" href="#">Log out</a></li>
</ul>
</div>