how do I add the ability for logged-in users to contact the administrator?

Question

At the moment the only way for people to contact the administrator is from the log-in form.

NikE · Accepted Answer

Unfortunately, the option for "please contact your JIRA administrators." is only avaiiable on the log-in form as you describe.  One alternative would be to post a banner message (admin panel ->issues -> User Interface -> Announcement Banner) though this is most commonly used for when setting up an account or making changes.