IRS Form 8879‑C – Fillable PDF for Corporate Tax Signature

What Is Form 8879‑C?

Form 8879‑C, IRS e‑File Signature Authorization for Form 1120, is the electronic signature worksheet that corporations use to authorize the electronic filing of their corporate income tax return (Form 1120). The form confirms that the corporate officer or authorized person has reviewed the return and consents to its electronic submission.

How to Fill Out Form 8879‑C Online

Instead of downloading the PDF and opening it in a separate editor, simply click the "Fill out this form" button on this page. The Formize PDF Filler app will load in your browser, allowing you to complete every field, add your electronic signature, and save or submit the document—all without leaving the site.

Common Mistakes to Avoid

• Incorrect EIN: Double‑check the Employer Identification Number; a typo will delay processing.
• Missing Signature: The form is invalid without a valid electronic signature from an authorized officer.
• Wrong Tax Year: Ensure the tax year matches the accompanying Form 1120.
• Incomplete Contact Info: Provide a current phone number and email; the IRS may need to reach you.

Where to Submit the Signed Form

After you finish, download the completed PDF and attach it to your e‑file submission in the tax software you are using. If you are filing manually, mail the signed Form 8879‑C to the address listed in the Form 1120 instructions.

Need Assistance?

The IRS provides detailed instructions on the form itself. For any uncertainties, consult a qualified tax professional. Remember, Formize does not offer live support, but the built‑in help tips in the filler guide you through each field.