Administrators, commonly known as admins or sysops (system operators), are Wikipedia editors who have been granted the technical ability to perform certain special actions on the English Wikipedia, including the ability to block and unblock user accounts and IP addresses from editing, edit fully protected pages, protect and unprotect pages from editing, delete and undelete pages, rename pages without restriction, and use certain other tools.
They are never required to use their tools, and must never use them to gain an advantage in a dispute in which they are involved.
Admins are selected by the Wikipedia community at Wikipedia:Requests for adminship through an often grueling review process. Go there if you would like to nominate someone to be an admin (including yourself).