Form 8879, the IRS e-file Signature Authorization, is the document a taxpayer signs to authorize an Electronic Return Originator (ERO) to transmit their return electronically and, where applicable, to enter or generate the taxpayer's PIN.
Why it matters to a preparer
You need a completed, signed 8879 on file before you transmit a client's return — it isn't filed with the IRS, but per the Form 8879 instructions you're required to retain the completed Form 8879 itself for three years from the return due date or the IRS received date, whichever is later. When the taxpayer isn't signing in your physical presence, IRS Publication 1345 requires their identity to be verified through an identity-verification method such as knowledge-based authentication or document-and-selfie verification at NIST IAL2, before that signature counts.
Publication 1345 puts other supporting materials — Form 8453 and its attachments, copies of Forms W-2 and 1099-R, signed consents, a copy of the return, and the acknowledgment file — on a shorter clock: retained only until the end of the calendar year, not the 8879's three years.
How it works
In practice: you prepare the return, the client reviews it, and then signs Form 8879 — either in person (verified the traditional way, e.g. reviewing a photo ID) or remotely, in which case the identity-verification step runs first and the document unlocks for signing only after it passes.
For remote signings, Publication 1345 requires identity verification for each transaction; the multi-year-business-relationship allowance applies only to in-person transactions — so build the check into every remote 8879 rather than assuming a prior check carries forward. Handling this through an e-signature tool built into a broader workflow, rather than a printed form, keeps the identity-verification step, the signed document, and the audit trail together automatically — and gives you a single place to point to if a client or the IRS ever asks how a particular signature was verified. See our full guide to e-signing Form 8879 remotely for the complete rules and record-keeping requirements.