suru verb (special), transitive verb
Formal verb used for signing one's name, especially on official documents. Often used in the pattern 〜に署名する or simply 署する.
契約書に署する。
Sign the contract.
彼は書類に署名を署した。
He signed his name on the document.
More common and neutral verb for signing. 署する is more formal and less frequently used in everyday speech.
Derived from the kanji 署 (sign, government office) combined with the verbal suffix する. The exact historical derivation is uncertain, but it follows the pattern of many Sino-Japanese verbs.