You might be able to put the code into the innerHTML of an element…
<a href="tel:5551234567">Call (555)123-4567</a>
you could add css styling there too, or in the HTML Header
To get rid of the underline, use this in your HTML Header…
text-decoration: none !important;
And you can select any font in the Typography Inspector - NOTE: All links will not be underlined.