What is Form I-9?

For small businesses, hiring a new employee (whether they’re your first hire or not) is a big deal. It signals business growth, a measure of success, and more.

But hiring a new employee also comes with its own host of new challenges and responsibilities—chief among them, wading through all of the required new hire and payroll paperwork and taxes. There’s a lot for both new and seasoned employers to keep track of.

That’s why we created our payroll knowledge center: to make the world of payroll taxes and new hire paperwork easier for employers to understand and navigate.

In this guide, we explain Form I-9, the Employment Eligibility Verification form. We cover all the basics that employers need to know about this key part of new hire paperwork, including:

What Form I-9 is
Why you need to have employees fill it out
How the form works (including acceptable documents)
What employers need to do with completed I-9 forms

What is Form I-9?

If you’re just looking for the basics on Form I-9, here are the key points to know about it:

What’s reported on Form I-9: Employee citizenship status and eligibility for employment in the United States
When it’s completed: Upon hire of each new employee
Who needs to fill it out: Nearly all employees in the U.S.

Form I-9 is a document that the United States Citizenship and Immigration Services (USCIS) requires employers to collect from all new hires on the first day they start work. Born out of the 1986 Immigration Reform and Control Act (IRCA), the document serves to enable employers to validate a new employee’s eligibility to work in the U.S.

The typical I-9 form includes details about an employee’s:

Social security number and other personal details
Citizenship status (U.S. citizen or noncitizen)
Eligibility to work in the U.S.

In addition to having the employee fill out these details (in Section 1 of the form), employers are also required to collect acceptable documents from an employee and complete Section 2 of the I-9 form.

How is Form I-9 different from Form W-4?

Form W-4 and Form I-9 are similar in that they’re both considered part of new hire paperwork—meaning they need to be filled out whenever a new employee is hired.

The key difference between the two is the information they include. Whereas Form I-9 is designed to verify an employee’s employment eligibility, Form W-4 is used to determine payroll tax withholding amounts.

For more on IRS Form W-4, reference the guide here.

How is Form I-9 different from Form W-9?

Form W-9 is also considered a component of the paperwork required when you form a new working relationship. The difference between Forms I-9 and W-9 is twofold:

Form W-9 is filled out by independent contractors, whereas Form I-9 is required only for new employees
Form W-9, similar to Form W-4, is used for tax reporting purposes

For more on IRS Form W-9, reference our guide here.

Why employees need to fill out Form I-9

In 1986, the U.S. passed the Immigration Reform and Contract Act (or IRCA). The new law made it illegal for U.S. companies to knowingly employ undocumented immigrants. As part of that act, the USCIS placed the responsibility of verifying a new employee’s citizenship status and eligibility to work in the U.S. squarely on the shoulders of all U.S. employers.

Form I-9 was created to enable employers to verify that information, and to establish a mechanism for USCIS to check in on employee eligibility to work. From that, the list of acceptable documents to certify employees’ citizenship and work status was laid out.

Do I need to have employees fill out Form I-9?

In short, if you’re hiring a new employee, you need to have them fill out Form I-9 as a part of their new hire paperwork, and you need to collect the acceptable documents to fill out Section 2 of the I-9 form yourself.

That said, the USCIS outlines a few notable exceptions to Form I-9 requirements:

Individuals who perform “casual domestic work” on a “sporadic, irregular, or intermittent basis” are not required to fill out Form I-9 or provide acceptable documents to verify work status.
Employees who aren’t physically located in the U.S. (remote employees, for example) are also not required to complete Form I-9.
Independent contractors do not require an I-9 form (that said, Federal law still prohibits U.S. companies from knowingly working with an independent contractor who isn’t authorized to work in the U.S.)

If none of these situations apply to a new hire, it’s safe to assume that you are required to collect and complete an I-9 form for them.

How Form I-9 works

Now that we’ve established whether or not you’re required to collect and complete Form I-9 for a new employee, let’s talk about how the form works. Unlike many payroll and onboarding paperwork documents, Form I-9 must be completed by both the employee and the employer.

Section 1

On their first day of work (or earlier), you need to provide an I-9 form, along with complete instructions for the form and the list of acceptable documents to your new employee.

The new employee will fill out Section 1, which includes personal details and establishes their stated citizenship status and employment eligibility as:

A citizen of the U.S.
A noncitizen national of the U.S.
A lawful permanent resident
An alien authorized to work

The employee then signs Section 1 of the form to certify their stated citizenship status.

When employees should fill out Form I-9

Section 1 of the I-9 form must be completed and signed by a new employee by the end of their first day of work. For that reason, you can begin the process as soon as they’ve accepted an official job offer.

Section 2

Section 2 is the employer’s portion of the I-9 form. It must be filled out and signed by the employer within 3 days of the employee’s date of hire. So, for example, if a new employee begins work on Monday, you must complete and sign the I-9 form by Thursday.

In Section 2, the employer is required to examine the acceptable documents an employee provides as proof of their citizenship and eligibility to work and to document key details from each.

The employer (or an authorized representative) then signs Section 2 to affirm that they’ve examined the documents and believe the employee is authorized to work in the U.S.

Acceptable documents to accompany Form I-9

In order for an employer to complete Section 2, employees need to present original documents from the list of acceptable documents. Employees can bring in either:

1 document from List A
OR 1 document from List B and 1 document from List C

List A documents are approved to serve as evidence of both identity and employment authorization; a valid U.S. passport, for example, satisfies List A requirements. List B documents, on the other hand, establish an individual’s identity only (state driver’s licenses, for example). Therefore, List C documents are needed in addition to prove an employee’s employment authorization (a U.S. Social Security card falls under this category).

The USCIS provides a full list of documents included in each category here.

What to do with completed I-9 forms

Now that both you and your new employee have completed each section of Form I-9, you’re probably wondering where and how to file it. Form I-9 is unique with regard to much of the new hire and payroll paperwork employers are required to complete, because it isn’t filed with any federal or state agency.

Instead, employers must keep an I-9 form for each employee at the ready. Should an official from the U.S. Department of Homeland Security (DHS), Department of Labor (DOL), or Department of Justice (DOJ) ask for it, you must be able to furnish an I-9 form for every current employee.

Generally, you should retain Form I-9 for each employee for 3 years after the date of hire or 1 year after employment is terminated (whichever occurs later).

Wrapping up

While you aren’t required to file I-9 forms with any government agency, it’s still vital to have them completed and on-hand for every person you employ. To wrap up, here are the key details you need to know about Form I-9:

Form I-9 verifies an employee’s citizenship status and eligibility to work in the U.S.
Nearly every statutory employee in the U.S. must complete Section 1 and provide acceptable documents to certify their citizenship and work status

Download the form on the USCIS website and see the list of acceptable documents