Ohio Rev. Code § 3121.23: Service.

Except when a provision specifically authorizes or requires service other than as described in this section, service of any notice on any party, a financial institution, or payor, for purposes of Chapters 3119., 3121., 3123., and 3125. of the Revised Code, shall be made by ordinary first class mail directed to the addressee at the last known address or, in the case of a corporation, at its usual place of doing business. A notice shall be considered to have been served when it is mailed.