Ohio Revised Code Title XLI. Labor and Industry § 4123.752

Service of process under section 4123.751 of the Revised Code shall be served by the officer to whom the same shall be directed or by the sheriff of Franklin county, who may be deputized for such purposes by the officer to whom the service is directed, upon the secretary of state by leaving at his office, at least fifteen days before the return day of such process, a true and attested copy thereof, and by sending to the defendant, by registered mail, postage prepaid at least fifteen days before the return day of such process, a like true and attested copy thereof, with an endorsement thereon of the service upon the secretary of state, addressed to such defendant at his last known address. The registered mail return receipt shall be attached to and made a part of the return of service of such process.