The admins are site administrators, meaning they are employees of Reddit who help keep the site up and running. Admins will have a red [A] or red Snoo icon on their user profile and are also able to distinguish their comments with a red [A] or red Snoo icon when speaking officially.
The admins enforce the rules of reddit that apply to every community. Be familiar with these rules. Failure to follow these rules may earn a user a site-wide ban or result in the closing down of an entire community.