The Practitioner PIN method is an alternative way for taxpayers to authorize their tax professional to electronically file their tax return(s) without having to sign and mail Form 8879. Instead, the tax professional can use their own Practitioner PIN to electronically sign the taxpayer's return(s) on their behalf. This method is only available to tax professionals who have been granted this authorization by the IRS. Taxpayers who are unable to use the Practitioner PIN method must still complete and mail Form 8879.