Years ago when adding a markup about telephone number we would simply do write it down:
+63 2 46567898
For emails, we could a somewhat different one such as:
<a href='mailto:firstname.lastname@example.org'>Email me!</a>
Telephone number links have evolved since. instead of writing the telephone number, we can add the
<a href='tel:+63246567898'>Call Me</a>
Now, Skype has stepped up its game. It doesn’t use the
tel: protocol. Instead, it uses the
callto:. When clicking on a link with the
callto protocal would open up Skype if you have it installed.
<a href='callto:+63246567898'>Call Me</a>
If this isn’t something you want, you can try Skype’s contact buttons. They are quite nice and customizable.