Kaynak
Demo
<!--Jquery-->
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js" integrity="sha256-CSXorXvZcTkaix6Yvo6HppcZGetbYMGWSFlBw8HfCJo=" crossorigin="anonymous"></script>
<!--Floating WhatsApp css-->
<link rel="stylesheet" href="https://rawcdn.githack.com/rafaelbotazini/floating-whatsapp/3d18b26d5c7d430a1ab0b664f8ca6b69014aed68/floating-wpp.min.css">
<!--Floating WhatsApp javascript-->
<script type="text/javascript" src="https://rawcdn.githack.com/rafaelbotazini/floating-whatsapp/3d18b26d5c7d430a1ab0b664f8ca6b69014aed68/floating-wpp.min.js"></script>
<body>
<!--Div where the WhatsApp will be rendered-->
<div id="WAButton"></div>
</body>
<style>
body {
font-family: Arial, Helvetica, sans-serif;
}
</style>
<script type="text/javascript">
$(function() {
$('#WAButton').floatingWhatsApp({
phone: '908503026776', //WhatsApp Business phone number International format-
//Get it with Toky at [url]https://toky.co/en/features/whatsapp[/url].
headerTitle: 'Bize Whatsappdan ulaşabilirsiniz', //Popup Title
popupMessage: 'Merhaba size nasıl yardımcı olabilirim?', //Popup Message
showPopup: true, //Enables popup display
buttonImage: '<img src="https://rawcdn.githack.com/rafaelbotazini/floating-whatsapp/3d18b26d5c7d430a1ab0b664f8ca6b69014aed68/whatsapp.svg" />', //Button Image
//headerColor: 'crimson', //Custom header color
//backgroundColor: 'crimson', //Custom background button color
position: "right"
});
});
</script> 
