45 CFR § 681.23 - How are documents filed and served with the ALJ?
(a) Documents filed with the ALJ must include an original and two copies. Every document filed in the proceeding must contain a title (e.g., motion to quash subpoena), a caption setting forth the title of the action, and the case number assigned by the ALJ. Every document must be signed by the person on whose behalf the paper was filed, or his or her representative.
(b) Documents are considered filed when they are mailed. The date of mailing may be established by a certificate from the party or its representative, or by proof that the document was sent by certified or registered mail.
(c) A party filing a document with the ALJ must, at the time of filing, serve a copy of such document on every other party. When a party is represented by a representative, the party's representative must be served in lieu of the party.
(d) A certificate of the individual serving the document constitutes proof of service. The certificate must set forth the manner in which the document was served.