If you hire employees, then there is information that you need to secure for your records and forms that you must complete including the following: Employee’s Eligibility to Work in the United States Employee's Social Security Number (SSN) Employee's Withholding Employee's eligibility to work in the United States Employer must verify the identity and employment authorization of individuals hired for employment in the United States. Employer use Form I-9, Employment Eligibility Verification PDF, for this purpose. All U.S. employers must properly complete Form I-9 for every individual they hire for employment in the United States. This includes citizens and noncitizens. Both employees and employers (or authorized representatives of the employer) must complete the form. Back to top Employee's Social Security Number (SSN) You are required to get each employee's name and Social Security number (SSN) and to enter them on Form W-2 (this requirement also applies to resident and nonresident alien employees). If your employee does not have their social security card readily available, then the Social Security Administration (SSA) offers Social Security number (SSN) verification and quick access to relevant forms and publications. Do not accept an ITIN in place of an SSN for employee identification or for work. An ITIN is only available to resident and nonresident aliens who are not eligible for U.S. employment and need identification for other tax purposes. You can identify an ITIN because it is a 9-digit number that begins with the number "9" and is formatted like an SSN (NNN-NN-NNN). Note: An individual with an ITIN who later becomes eligible to work in the United States must obtain an SSN. Back to top Employee's withholding To know how much income tax to withhold from employees' wages, you should have a Form W-4, Employee's Withholding Certificate, on file for each employee. Ask all new employees to give you a signed Form W-4 when they start work. Make the form effective with the first wage payment. If employees claim exemption from income tax withholding, then they must indicate this on their W-4. The amount of income tax withholding must be based on filing status and withholding adjustments as indicated on the form. If a new employee does not give you a completed Form W-4, then withhold tax as if the employee is single. Additional withholding may be required on wages paid to non-resident aliens. A Form W-4 remains in effect until the employee gives you a new one. If employees claim exemption from income tax withholding, then they must give you a new Form W-4 each year. If an employee gives you a Form W-4 that replaces an existing Form W-4, then begin withholding no later than the start of the first payroll period ending on or after the 30th day from the date you received the replacement Form W-4. For exceptions and invalid Forms W-4, refer to Publication 15, (Circular E), Employer's Tax Guide. You may also refer your employees to the tax withholding estimator. Remember that this application is to help employees to ensure that they do not have too much or too little income tax withheld from their pay. It is not a replacement for Form W-4, but most people will find it more accurate and easier to use than the worksheets that accompany Form W-4. They may use the results of this program to help them complete a new Form W-4, which they will submit to their employer. Special rules may apply to agricultural employers. For more information, please refer to Publication 51, (Circular A), Agricultural Employer's Tax Guide. Back to top Related Businesses with employees Employer Responsibilities When Hiring Foreign Workers Hiring household employees Publications About Publication 505, Tax Withholding and Estimated Tax