The format of fu is established in Kushiki-ryo (law on state documentary forms in the Yoro Code), and according to the format, the first line of fu begins with the opening sentence 'So-and-so (The senior official's name) gives a command to So-and-so (the subordinate official's name),' the second line contains the order and the closing line read, "Implement upon receipt."
公式令(律令法)にその書式が定められており、符は初行に○○○（上級の官司）符其×××（下級の官司）の書出に始まり、2行目より事実書（内容の記載）が行われて「符至奉行（符至らば奉行（文書の内容を実施）せよ）」の句が書止として付される。