2 U.S.C. § 384 — Service and filing of papers other than notice of contest

(a) Modes of service. Every paper that must be served — except the notice of contest itself, which is covered elsewhere — must be served on the party's attorney, or on the party directly if there's no attorney. Service can happen in three ways: (1) delivering a copy to the person directly; (2) leaving it at the person's main office with someone in charge there, or, if the office is closed or there's no office, leaving it at the person's home with someone at least sixteen years old who lives there; or (3) mailing it to the person's home or main office. Mailed service counts as complete the moment it's mailed. (b) Filing of papers with clerk. Every paper served on the opposing party after the notice of contest must also be filed with the Clerk, either before it's served or within a reasonable time afterward. (c) Proof of service. Papers filed after the notice of contest must come with proof showing when and how they were served, made either by a sworn statement from the person who served it or by a certificate from the party's attorney. If proof of service is missing, that doesn't make the service itself invalid.