examples of their doc:

<div class="panel panel-default">
  <div class="panel-body">
    Basic panel example
  </div>
</div>

<div class="panel panel-default">
  <div class="panel-body">
    Panel content
  </div>
  <div class="panel-footer">Panel footer</div>
</div>

<a href="#">Inbox <span class="badge">42</span></a>

<button class="btn btn-primary" type="button">
  Messages <span class="badge">4</span>
</button>
[download]

Source: http://getbootstrap.com/components/#badges