IRS Publication 1345, the Handbook for Authorized IRS e-file Providers, is the IRS's rulebook for Electronic Return Originators (EROs) — including the identity-verification requirements that govern signing Form 8879 remotely.
Why it matters to a preparer
Pub 1345 is the source document behind several rules preparers run into separately without realizing they share one origin: what counts as an acceptable e-signature on Form 8879, when identity verification is required for a remote signer, and which verification methods — such as knowledge-based authentication or document-and-selfie verification at NIST IAL2 — satisfy that requirement. If you've ever wondered why an e-signature tool insists on an identity check for some documents and not others, Pub 1345 is the reason.
It's also the reason two preparers can have very different-looking signing workflows and both be fully compliant: the handbook sets the requirement, not the specific software or exact steps used to meet it. Identity verification is sometimes mistaken for a feature a software vendor invented to justify a higher price; in reality it traces directly back to this specific federal requirement, not a vendor's marketing choice.
How it works
As an ERO, your obligations under Pub 1345 include verifying signer identity for remote 8879 transactions through an accepted method, retaining the signed 8879 and its supporting records, and keeping your e-file practices in line with what the handbook describes.
It's updated periodically by the IRS, so the practical move is to build your signing workflow around software that keeps pace with the current rules rather than trying to track every revision yourself. See our guide to e-signing Form 8879 remotely for how the identity-verification requirement plays out in practice, and treat the handbook as a reference to check when something about e-file or e-signing seems unclear, rather than something to memorize in full.