When electronically filing Form 7004 to request an extension, is a Form 8879 required for the taxpayer's signature?
When filing a Form 7004, the Form 8879 is not required.
A signature is required only when filing the Form 7004 with a payment to be made by electronic funds withdrawal. When an electronic payment is included, the electronic extension must be signed by the Practitioner PIN and Form 8878 will be activated and must be signed.
For more information, please review IRS Publication 4163, Modernized e-File (MeF) Information for Authorized IRS e-file Providers for Business Returns.