How do you add a social share button to a landing page that uses a template?

I'd like to add the social share button to existing landing pages. However, these pages were created using templates. I understand how to drop a social share button on a free form landing page, but how do you add the social share button to a landing page that uses a template?

Is this even possible? Or, would this have to be done at the template level? If so, please share how. Thanks!