Namu Myoho renge kyo is the transfer document

The transfer document for the last age [STS 3:25941]

"Our teacher said: "Last age" means the fifth five hundred years that begin the Final Dharma age. The "transfer document" is Namu-myoho-renge-kyo, a document that is handed down as proof of inheritance. There are two meanings in this transfer. One is the designation of successorship; the other is the bestowal of wealth. The designation of successorship means that Sakyamuni named as his heirs the practitioners of the Lotus Sutra. The passage of proof states, "[..desiring to make all beings] equal to me, without difference." (67) As for the transfer of wea1th, Sakyamuni also passed on to the practitioners of the Lotus Sutra his wisdom and the virtues he had obtained by observing the precepts. The passage of proof states, "We have obtained for ourselves the supreme jewel cluster without seeking it." (68) Thus the five characters of the daimoku constitute a transfer document." -- Ongi Kikigaki

There is no transfer document other than Namu Myoho renge kyo, the scrolls of the Gohonzon, Lotus Sutra, and writings of Nichiren Daishonin