When you receive the worker's Social Security number, file Form W-2c (Corrected Wage and Tax Statement), to show the worker's number. Not all forms are listed.Use Form I9 to verify the identity and employment authorization of individuals hired for employment in the United States. For example, the I9 form does not require employees to provide a Social Security number. Form I-765 – Application for Employment Authorization. 1. US Social Security Card 2. It is not illegal for an employer to ask you for your social security number (SSN). HOWEVER you are in no way obligated to provide your SSN. Fill out Section A and take the form to your employer. Update" questions on the Form N-400 (Application for. Naturalization).