Hello Ryan,
Thanks for submitting a question about creating a phone link. There is some HTML code mentioned in this forum post which brings up the default phone app for mobile devices or desktop computers. This might be the best solution since it will work for both mobile and desktop users.
However, to have a button that only shows for mobile devices will require some conditional coding. We don’t have the resources available to help with individual coding requests, but you should be able to find a code snippet on the web or request help from a developer.
Best,
Christopher M.