Harcourt Fenton Mudd's signature
A signature was one's own name written in one's handwriting for the purpose of indicating that one had read or approved of the contents of a document or report. A signature could also be provided as identifying evidence on one's records. Signatures given by famous individuals to fans were called autographs.
In 2259 of the alternate reality, Montgomery Scott refused to sign an order authorizing advanced long-range torpedoes to be loaded onto USS Enterprise without looking at the specifications first. When Captain James T. Kirk ordered him to sign, Scott resigned instead. (Star Trek Into Darkness)
Harry Mudd's signature appeared under his photo on the police record found in USS Enterprise's library computer. (TOS: "Mudd's Women")
In 2267, Yeoman Atkins showed James T. Kirk his signature on a fuel consumption report to prove to the aging captain that he had indeed signed it only moments ago, despite his not remembering having done so. (TOS: "The Deadly Years")
In 2380, the closing credits for the holo-movie Crisis Point: The Rise of Vindicta featured the signatures of the USS Cerritos' "lower decks" crew. (LD: "Crisis Point")