HTML

Bootstrap Offcanvas

<a class="btn btn-primary" data-bs-toggle="offcanvas" href="#offcanvasExample" role="button" aria-controls="offcanvasExample">
  Link with href
</a>
<button class="btn btn-primary" type="button" data-bs-toggle="offcanvas" data-bs-target="#offcanvasExample" aria-controls="offcanvasExample">
  Button with data-bs-target
</button>

<div class="offcanvas offcanvas-start" tabindex="-1" id="offcanvasExample" aria-labelledby="offcanvasExampleLabel">
  <div class="offcanvas-header">
    <h5 class="offcanvas-title" id="offcanvasExampleLabel">Offcanvas</h5>
    <button type="button" class="btn-close" data-bs-dismiss="offcanvas" aria-label="Close"></button>
  </div>
  <div class="offcanvas-body">
    <div>
      Some text as placeholder. In real life you can have the elements you have chosen. Like, text, images, lists, etc.
    </div>
    <div class="dropdown mt-3">
      <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-bs-toggle="dropdown">
        Dropdown button
      </button>
      <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton">
        <li><a class="dropdown-item" href="#">Action</a></li>
        <li><a class="dropdown-item" href="#">Another action</a></li>
        <li><a class="dropdown-item" href="#">Something else here</a></li>
      </ul>
    </div>
  </div>
</div>

bootstrap offcanvas

<button class="btn btn-primary" data-bs-toggle="offcanvas" data-bs-target="#mobile-nav">
    Link with href
</button>
<ul id="mobile-nav" class="offcanvas offcanvas-start">
</ul>