If you are filing your tax return using an online provider,
mail Form 8453 to the IRS within 3 business days after
you have received acknowledgement from your
intermediate service provider and/or transmitter that the
IRS has accepted your electronically filed tax return. If
you don’t receive an acknowledgement, you must contact
your intermediate service provider and/or transmitter.
Mail Form 8453, U.S. Individual Income Tax Transmittal for an IRS e-file ... to:
Internal Revenue Service
Attn: Shipping and Receiving, 0254
Receipt and Control Branch
Austin, TX 73344-0254