305.03(a) Filing Date When Priority Mail Express® Is Used
For permitted paper filings (see TMEP §301.02), Trademark Rule 2.198 provides a procedure for obtaining a filing date as of the date that correspondence is deposited as Priority Mail Express® with the USPS, as shown by the "date accepted" on the Priority Mail Express® label or other official USPS notation. 37 C.F.R. §2.198(a).
If the USPS deposit date cannot be determined, the filing date is the date the USPTO receives the submission. 37 C.F.R. §2.198(b).