bootstrap 5
<button class="btn btn-primary" type="button" data-bs-toggle="offcanvas" data-bs-target="#offcanvasTop" aria-controls="offcanvasTop">Toggle top offcanvas</button>
<div class="offcanvas offcanvas-top" tabindex="-1" id="offcanvasTop" aria-labelledby="offcanvasTopLabel">
<div class="offcanvas-header">
<h5 id="offcanvasTopLabel">Offcanvas top</h5>
<button type="button" class="btn-close text-reset" data-bs-dismiss="offcanvas" aria-label="Close"></button>
</div>
<div class="offcanvas-body">
...
</div>
</div>