A short code is a small block of text inside a set of square brackets [ like this ] that does something special like inserts a styled button, an accordion, or a weather forecast (to name a few). I see that you are a member of the Killington site and are a staff member. I don’t think you’d have a need to use a short code in your current role on the KP site. Short codes are typically only available to users who can edit pages.
Hope this helps,