What Is Form 8878: Signature for a Tax Extension?

Form 8878, IRS e-file Signature Authorization for Form 4868 or Form 2350, is a document that authorizes a tax professional to electronically file an application for an extension of time to file a tax return. This form is not the extension application itself but is the official record of the taxpayer’s consent.

Purpose of Form 8878

The function of Form 8878 is to provide a legal substitute for a physical signature when a tax professional, or Electronic Return Originator (ERO), e-files an extension request. It is used with either Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return, or Form 2350, Application for Extension of Time to File U.S. Income Tax Return.

By signing Form 8878, the taxpayer affirms that the information is accurate and grants the ERO permission to use an electronic signature, often a Personal Identification Number (PIN), on the extension form. This process is part of the Practitioner PIN method for signed, electronic submissions from tax professionals.

Information Required to Complete the Form

To complete Form 8878, the taxpayer’s name and Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN) are required. If filing a joint return, the spouse’s name and SSN or ITIN are also needed.

Part I, Tax Return Information, must align with the figures from the extension application. This includes the total estimated tax liability for the year, the total tax payments already made, and the resulting balance due.

In Part II, the Taxpayer Declaration, the taxpayer signs and checks a box to authorize the ERO to enter their self-selected PIN. The taxpayer chooses a five-digit PIN, which cannot be all zeros, to serve as an electronic signature. Part III is reserved for the ERO’s information and signature.

The Authorization and Filing Process

The taxpayer must return the completed and signed form to their ERO, which can be done by hand delivery, mail, fax, or secure email. The ERO cannot transmit the electronic extension request to the IRS until they have this signed form.

After receiving the form, the ERO can electronically submit the extension application to the IRS. The signed Form 8878 is not sent to the IRS. Instead, the ERO must retain the completed form for three years from the return due date and make it available for inspection if requested by the IRS.