
Zendocs is not affiliated with the Internal Revenue Service (IRS).
Everything You Need to Know About IRS Form SS-4
What is Form SS-4?
Form SS-4 is the official IRS application for an Employer Identification Number (EIN). This nine-digit number acts as a federal tax ID for your business, trust, estate, or organization. It is required for filing certain tax returns, opening a business bank account, hiring employees, or applying for business licenses. Unlike a Social Security Number (SSN), which identifies individuals, an EIN identifies entities.
Who needs an EIN (via SS-4)?
Not every taxpayer needs an EIN, but many do. You must file Form SS-4 if you:
- Operate a corporation, partnership, or multi-member LLC.
- Hire employees and must file payroll taxes.
- Run a nonprofit, trust, estate, or pension plan.
- File excise taxes (alcohol, tobacco, firearms, fuel, etc.).
Act as a withholding agent for nonresident aliens. - Need to establish business credit or a separate bank account under a business name.
- Even sole proprietors may apply for an EIN to keep their SSN private and separate personal vs. business finances.
Why is an EIN important?
- Acts as your business identity number for the IRS and banks.
- Required to process federal employment and business taxes.
- Used when applying for business loans, credit lines, or licenses.
- Ensures compliance with IRS regulations.
- Protects owners from using their SSN on business documents, lowering identity theft risks.
Submission methods
- Online: Fastest; EIN issued immediately (available to U.S.-based applicants).
- Fax: 4 business days (confirmation sent back).
- Mail: Up to 4 weeks.
- Phone: For international applicants only.
Validity & Maintenance
- EINs never expire and are tied permanently to the entity.
- If business ownership or structure changes (e.g., sole proprietor converts to a corporation), a new EIN may be required.
- The IRS maintains EIN assignments in its Centralized Authorization File (CAF).
Common mistakes to avoid
- Using SSN instead of applying for an EIN when required.
- Applying for multiple EINs unnecessarily.
- Selecting the wrong entity type (leads to wrong tax obligations).
- Forgetting to include responsible party details.
FAQ
Simple 3-Step Process

1. Fill Out The Form
Fill in your details and information, add date and customize as needed

2. Add Your Signature
Add legally-binding signature by drawing, uploading, or typing

3. Download or share
Your form is ready, download, share link or send via email instantly

1. Fill Out The Form
Fill in your details and information, add date and customize as needed

2. Add Your Signature
Add legally-binding signature by drawing, uploading, or typing

3. Download or share
Your form is ready, download, share link or send via email instantly

1. Fill Out The Form
Fill in your details and information, add date and customize as needed

2. Add Your Signature
Add legally-binding signature by drawing, uploading, or typing

3. Download or share
Your form is ready, download, share link or send via email instantly

1. Fill Out The Form
Fill in your details and information, add date and customize as needed

2. Add Your Signature
Add legally-binding signature by drawing, uploading, or typing

3. Download or share
Your form is ready, download, share link or send via email instantly
What our users are saying
I was skeptical about editing pdfs on my phone, but Zendocs made it work smoothly. Filled out a freelance w9 while waiting for my coffee. No issues at all.
I'm a screenwriter and mark up my drafts often. Tried the annotate pdf tool here – it was actually pleasant to use. Notes stuck where I placed them, colors were clear, and export kept everything intact. Beats printing 80 pages every time.
Used ZenDocs to split up a 100-page policy doc into smaller team manuals. It was quick, intuitive, and didn't crash once – even with that massive file.
Compiled my speaker bio, session outline, and visual aids into one file for a conference. ZenDocs let me combine them fast and add bookmarks for each section. This made navigating during my talk so much easier. I even re-uploaded the final version to make a few changes – every step was smooth. Really appreciated how consistent the UI was.
I needed to add quick comments to student feedback forms and the annotate pdf feature on zen docs made it painless. No crashes, super clean interface – definitely easier than Adobe's bloated editor.
ZenDocs has the cleanest interface I've used. Edited a PDF proposal, reordered some sections, and exported without hassle. It just works.
I was skeptical about editing pdfs on my phone, but Zendocs made it work smoothly. Filled out a freelance w9 while waiting for my coffee. No issues at all.
I'm a screenwriter and mark up my drafts often. Tried the annotate pdf tool here – it was actually pleasant to use. Notes stuck where I placed them, colors were clear, and export kept everything intact. Beats printing 80 pages every time.
Used ZenDocs to split up a 100-page policy doc into smaller team manuals. It was quick, intuitive, and didn't crash once – even with that massive file.
Compiled my speaker bio, session outline, and visual aids into one file for a conference. ZenDocs let me combine them fast and add bookmarks for each section. This made navigating during my talk so much easier. I even re-uploaded the final version to make a few changes – every step was smooth. Really appreciated how consistent the UI was.
I needed to add quick comments to student feedback forms and the annotate pdf feature on zen docs made it painless. No crashes, super clean interface – definitely easier than Adobe's bloated editor.
ZenDocs has the cleanest interface I've used. Edited a PDF proposal, reordered some sections, and exported without hassle. It just works.
I was skeptical about editing pdfs on my phone, but Zendocs made it work smoothly. Filled out a freelance w9 while waiting for my coffee. No issues at all.
I'm a screenwriter and mark up my drafts often. Tried the annotate pdf tool here – it was actually pleasant to use. Notes stuck where I placed them, colors were clear, and export kept everything intact. Beats printing 80 pages every time.
Used ZenDocs to split up a 100-page policy doc into smaller team manuals. It was quick, intuitive, and didn't crash once – even with that massive file.
Compiled my speaker bio, session outline, and visual aids into one file for a conference. ZenDocs let me combine them fast and add bookmarks for each section. This made navigating during my talk so much easier. I even re-uploaded the final version to make a few changes – every step was smooth. Really appreciated how consistent the UI was.
I needed to add quick comments to student feedback forms and the annotate pdf feature on zen docs made it painless. No crashes, super clean interface – definitely easier than Adobe's bloated editor.
ZenDocs has the cleanest interface I've used. Edited a PDF proposal, reordered some sections, and exported without hassle. It just works.