New employees must fill out many government-mandated forms when starting a job. Some forms verify your identity while others help determine how much tax will be taken from your paycheck. You will also need to provide proof of your identity, and proof that you have the right to work legally in the United States.

Your W-2

The W-2 form is issued annually, usually in January. It's a record of an employee's earnings, employer-sponsored retirement contributions, and federal, state, and local taxes. It also reveals how much you've paid into the Social Security and Medicare systems. The W-2 provides your employer's business address and tax identification number, and you receive multiple copies to give to each taxing authority. No identification is required to get your W-2. It's mailed to your address or administered with your paystub. The W-2 is the source of the income data that taxpayers use to file income taxes.

Your W-4

The W-4 form is filled out on your first day on the job and also doesn't require identification paperwork. It helps your employer determine how much in federal tax to withhold from your paycheck. You'll either declare yourself "single" or "married," or "married, but withhold at higher single rate." You'll also claim your dependents on this form; more dependents equal less tax removed from your pay. Be wary of claiming too many exemptions, however, as this may result in too little tax being withheld, and you might be penalized at tax time as a result.

Your I-9

The I-9 is the form that employers use to determine whether an employee can lawfully work in the United States. The I-9 is used in conjunction with the W-4 when a new employee begins a job; the forms are filled out at the same time. Employees must provide at least two official documents that prove legal working status. These documents include a U.S. Passport, permanent resident card, employment authorization document, a state driver's license, a U.S. identification card, a school identification with a photograph, a voter registration card, a military card, a Social Security card and a birth certificate. Other documents might qualify as well; your employer will be able to confirm eligibility.

Why They're Needed

These documents, which are difficult to reproduce and are essential for proving legal rights, are used to ensure that employers and employees are paying their legal share of taxes. The documents reassure employers that new employees aren't in the country illegally. Employee earnings, reported on the W-2, reflect the information provided on the I-9 and W-4 forms. These earnings are also reported to the federal government, and if the employee doesn't file a tax return, it won't be long before Uncle Sam comes knocking for his due.