<a

 href="https://wa.me/5555996640927"

 style="

  position: fixed;

  width: 60px;

  height: 60px;

  bottom: 0.8rem;

  right: 0.8rem;

  background-color: #25d366;

  color: #fff;

  border-radius: 50px;

  text-align: center;

  font-size: 30px;

  box-shadow: 1px 1px 2px #888;

  z-index: 101;

  transition: all 0.2s ease-in-out;

 "

 id="whatsappButton"

 target="_blank"

>

 <i style="margin-top: 16px" class="fab fa-whatsapp"></i>

</a>

<style>

 @media (max-width: 768px) {

  #whatsappButton {

   bottom: 75px !important;

  }

 }

</style>

<script>

 (function moveWhatsappButtonOnScroll() {

  var button = document.getElementById("whatsappButton");

  if (!button || !window.scrollTopThreshold) return;

  window.addEventListener("scroll", function scrollListener() {

   var winScroll =

    document.body.scrollTop || document.documentElement.scrollTop;

   button.style.right =

    winScroll > window.scrollTopThreshold ? "5rem" : ".8rem";

  });

 })();

</script>