Sign Tax Forms Online

Forms you give to a business, and forms you file with the IRS

The question “can I e-sign this tax form?” has two different answers. Forms you hand to a client, employer, bank or platform are collected by that business, and it decides whether an electronically signed PDF is acceptable. Forms that go to the IRS follow the IRS's own signature rules. Knowing which kind you are holding saves a rejected form.

Forms usually signed and returned as a PDF

• Form W-9 (Request for Taxpayer Identification Number and Certification): you give it to the business that will pay you or open an account for you. The IRS allows requesters to collect W-9s electronically.
• Form W-4 (Employee's Withholding Certificate): goes to your employer, not the IRS. Employers can accept it electronically; many use their payroll system, others accept a signed PDF.
• Form W-8BEN: for non-US individuals who receive US-source income, given to the payer or platform. It certifies your foreign status and any treaty benefit you claim. Many platforms collect it in their own online flow.
• Engagement letters and consent forms from an accountant or tax preparer, such as a fee agreement.

Forms with their own IRS signing process

• Your tax return: e-filed returns are signed inside your tax software, typically with a Self-Select PIN. If you mail a paper return, check the IRS rules for that form before using anything other than an ink signature.
• Forms 8879 and 8878 (e-file signature authorization): signed through your preparer's system, which must meet IRS identity-verification rules.
• Forms 2848 and 8821 (power of attorney and tax information authorization): electronic signatures are accepted only when the form is submitted through the IRS online tool. Faxed or mailed copies need a handwritten signature.

Check these before you sign a W-9

1. Line 1 is the name on your tax return. A single-member LLC that is disregarded for tax purposes puts the owner's name here and the LLC name on line 2.
2. Exactly one federal tax classification box is ticked (line 3a on the 2024 revision).
3. The TIN in Part I matches line 1: your SSN for an individual or sole proprietor (or an EIN if you have one), the business's EIN for a company.
4. Only cross out item 2 of the certification if the IRS has told you that you are subject to backup withholding and has not since told you that it stopped.
5. Date the form on the day you sign it.

How to sign a tax form with SigPDF

1. Download the current form from the requester or from IRS.gov and open it in the editor above.
2. IRS forms are fillable PDFs: type into the fields shown under Form Fields.
3. Draw or type your signature and place it on the “Signature of U.S. person” or employee signature line.
4. Add the date with Add Date, download the signed PDF, and send it the way the requester asked.

Fields that hold one character per box, flat forms with no fields and other form problems are covered in how to fill and sign a PDF form.

A W-9 contains your SSN or EIN. SigPDF never sees it, but email is not encrypted end to end, so use the requester's secure portal if they have one.