IRS Form 8879‑C – Fillable Corporate E‑File Signature Authorization

Form 8879‑C, IRS E‑File Signature Authorization for Corporations, is the official document that authorizes the IRS to accept an electronically filed corporate income‑tax return (Form 1120, 1120‑S, 1120‑F, etc.). Instead of mailing a paper signature, corporations can sign electronically using this fillable PDF, saving time and reducing errors.

What is Form 8879‑C?

The form serves as a written declaration that the corporate officer signing the return has reviewed the return, the information is accurate, and the corporation authorizes the IRS to process the e‑filed return. It must be signed by an authorized officer (president, treasurer, or other corporate officer) and attached to the electronic filing.

How to Fill Out Form 8879‑C with Formize

Instead of downloading the PDF and opening a separate editor, simply click the "Fill out this form" button on this page. The Formize PDF Filler app will load instantly, letting you complete every field directly in your browser.

• Step 1: Click the orange "Fill out this form" button.
• Step 2: Wait a few seconds for the Formize app to load.
• Step 3: Enter the corporation’s name, EIN, tax year, and other required data.
• Step 4: Add the electronic signature of the authorized officer.
• Step 5: Click "Save" to download the completed PDF, then attach it to your e‑filed return.

Common Mistakes & Tips for a Smooth Submission

• Incorrect EIN: Double‑check the nine‑digit Employer Identification Number; a typo will cause the return to be rejected.
• Wrong Tax Year: Use the calendar year or fiscal year that matches the corporate tax return you are filing.
• Missing Signature: The form is invalid without a clear electronic signature. Use the built‑in signature field—do not draw a signature in a comment box.
• Unsigned Attachments: If you file multiple returns (e.g., Form 1120‑S and Schedule K‑1), each must have its own Form 8879‑C signed.
• Saving Errors: After completing the form, click "Download" to store a copy on your computer. Do not rely solely on the browser’s temporary cache.

Where to Find Help and Additional Resources

For detailed instructions, see the IRS Instructions for Form 8879‑C. If you have questions about eligibility, signing authority, or e‑file technical issues, visit the IRS Help & Resources page or contact your tax professional.