39 CFR 959.9: Filing documents for the record.

(a) All documents required under this part must be filed using the electronic filing system unless the presiding officer permits otherwise. If both parties are participating in the electronic filing system, separate service upon the opposing party is not required. Otherwise, documents shall be served personally or by mail on the opposing party, noting on the document filed, or on the transmitting letter, that a copy has been so furnished.

(b) Documents shall be dated and state the title of the proceeding and, except initial petitions, the docket number. Documents submitted using the electronic filing system are considered filed as of the date/time (Eastern Time) reflected in the system. Documents mailed to the Recorder are considered filed on the date mailed as evidenced by a United States Postal Service postmark. Filings by any other means are considered filed upon receipt by the Recorder of a complete copy of the filing during normal business hours.