You can add the "Contact Us" option to the community footer. This way, if your community members need to contact you in private, they can email you. Where admins can add this email?
Admin Panel> Settings> General Settings> Email> Save changes:
Then, you need to make sure that in Admin Panel> Theme> Footer, you are changing the setting to "Automatically Generate Footer". You have option to add customized footer as well.
Where does this email or "Contact Us" option get displayed? It gets displayed on the right-side menu in home, next to the other footer option.