IRS Publication 3112
requires transmitters to validate that they are submitting returns only for Authorized IRS e-file Providers. To comply with IRS requirements, TaxACT requires prepares to submit a copy of their IRS e-file Application Summary. If you obtained your EFIN in the current year, you can also provide a copy of your EFIN Acceptance Letter. This one-time verification process needs to be completed for each EFIN used in your office.
You can submit a copy of your Application Summary through e-mail to EFINcertificate@TaxACTService.com
or fax it to 319-447-4674 (Attention: EFIN Verification). Once your EFIN letter has been processed, you will receive a confirmation e-mail stating TaxACT has received your EFIN verification.
You can find out more information about Electronic Filing ID Numbers (EFIN) in the IRS's FAQs