Documentación Plugin Chat
https://developers.facebook.com/docs/messenger-platform/discovery/customer-chat-plugin/?translation
Fontawesome (Iconos)
HTML Chat WhatsApp
<a id="app-whatsapp" target="_blanck" href="https://api.whatsapp.com/send?phone=50200000&text=Hola! me pueden apoyar?">
<i class="fab fa-whatsapp"></i>
</a>
HTML Chat Messenger
<a id="app-messenger" target="_blanck" href="https://m.me/abelosh">
<i class="fab fa-facebook-messenger"></i>
</a>
Estilos iconos WhatsApp y Messenger
#app-messenger, #app-whatsapp{
position: fixed;
right: 24px;
bottom: 25px;
width: 60px;
z-index: 1000;
display: none;
}
#app-whatsapp{
bottom: 95px;
display: block;
}
#app-messenger i, #app-whatsapp i{
font-size: 63px;
}
#app-whatsapp i{
color: #1ebea5;
}
#app-messenger i{
color: #0084ff;
}
Estilos Media Queries
@media screen and (max-width: 766px){
#fb-root{
display: none;
}
#app-messenger{
display: block;
}
}