How to make phone number a Click to Call on Phone?

After making various finding we come to conclusion to have following

    Wrap all phone numbers in hyperlinks with the tel: schema.
    Always use the international dialing format.

NIST Telephone Time-of-Day Service 
<a href="tel: 1-303-499-7111"> 1 (303) 499-7111</a>

This we found on google developer page and found it working

https://developers.google.com/web/fundamentals/native-hardware/click-to-call/

If you want to detect phone browser etc following articles will be useful

http://stackoverflow.com/questions/26088523/click-to-call-html

https://knowledge.hubspot.com/articles/kcs_article/cos-general/how-to-make-a-click-to-call-button-for-your-website

http://stackoverflow.com/questions/1164004/how-to-mark-up-phone-numbers