It is possible to make a telephone number clickable. On devices that have the ability to make telephone calls, this will allow users to tap on a link and start a phone call.
You can do this by adding a hyperlink. This is done by highlighting some text and clicking the hyperlink (chain) icon.
Instead of putting in a regular hyperlin with the https:// you can use the tel:// prefix. For example. to link to the SMILE telephone nuber the url that you would input into the hyperlink location would be tel://08003583608.