In the event that you might want to protect the character of your Company Secretary for any reason, you can designate a nominee secretary to assume their position on public record. Some individuals don't wish for their details to be disclosed the general public register of companies so they can delegate a candidate to secure their protection whilst as holding official rights and obligations as the organizations secretary.
A nominee secretary does not have any privilege to settle on decisions about how an organization works and operates, unless they are told to do as such by the genuine company secretary. The nominee's role is in name just, so the real secretary is still in charge of the organisation however they can approve the nominee to sign and complete certain documents and reports on their behalf.