Bootstrap CSS class .order-#

<div class="container">
  <div class="row">
    <div class="col">
      First, but unordered
    </div>
    <div class="col order-12">
      Second, but last
    </div>
    <div class="col order-1">
      Third, but first
    </div>
  </div>
</div>

<!-- responsive variations -->
<div class="col order-sm-3">Ordered column</div>
<div class="col order-md-3">Ordered column</div>
<div class="col order-lg-3">Ordered column</div>
<div class="col order-xl-3">Ordered column</div>