Telephone links are the ones that you tap to call a number on phone-capable devices. Of course, some devices are able to recognize phone numbers and provide the linking automatically, but it’s not always so.
In the example below, we use :tel within the HT
<!DOCTYPE html>
<html>
<head>
<title>How to Add Telephone Links with HTML</title>
</head>
<body>
<a href="tel:+21697000000">+216 97 000 000</a>
</body>
</html>
ML <a> tag. Note that tel: is much like a protocol, and not a feature.