Check out example codes for "link whatsapp to website". It will help you in understanding the concepts better.
Code Example 1
<!-- link the following URL to the desired icon or button in your code: https://wa.me/PhoneNumber (see the example below) remember to include the country code --> <a href='https://wa.me/27722840005' target='_blank'><i class= "fa fa-whatsapp"></i></a>
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