Except as required by any section of the Revised Code not in Chapters 5801. to 5811. of the Revised Code, a trust is not required to be evidenced by a trust instrument, but the creation of an oral trust and its terms may be established only by clear and convincing evidence.
Written instrument not required
Ohio Rev. Code Ann. § 5804.07, under Chapter 5804 | Creation, Modification, Revocation, And Termination.
Ohio Rev. Code Ann. § 5804.07