Private delivery services

If you choose, you may use a private delivery service, instead of the U.S. Postal Service, to mail in your form and tax payment. However, if, at a later date, you need to establish the date you filed or paid your tax, you cannot use the date recorded by a private delivery service unless you used a delivery service that has been designated by the U.S. Secretary of the Treasury or the Commissioner of Taxation and Finance. (Currently designated delivery services are listed in Publication 55 , Designated Private Delivery Services . See Need help? for information on obtaining forms and publications.) If you have used a designated private delivery service and need to establish the date you filed your form, contact that private delivery service for instructions on how to obtain written proof of the date your form was given to the delivery service for delivery. See Publication 55 for where to send the forms covered by these instructions.