The county supervisor shall designate every account upon which any sum shall be audited and allowed by the board, the amount so audited and allowed and the charges for which the same was allowed. He shall also deliver to any person who may desire it a certified copy of any account on file in his office on receiving from such person ten cents for every folio of one hundred words contained in such copy. And the supervisor shall endorse on every account allowed and ordered to be paid words indicating that it has been audited above the signature of the county supervisor.