Regardless of immigration status, immigrants working the United States generally are required to pay taxes, including income tax. Authorized workers can get social security numbers needed to file tax returns. Others who don't have the required work authorized visas to qualify for social security numbers can apply for individual tax identification number (ITIN) from the Internal Revenue Service. The ITIN is a tax processing number to ensure that workers, including unauthorized immigrants, pay taxes even if they do not have a social security number.
Many immigrants have ITINs, including those who are lawfully in the U.S. but do not qualify for social security numbers. For example, the spouse and children of temporary visa workers can also get an ITIN so they can be claimed as dependents on the tax return.
To learn more about the ITIN, including how to apply, check out The American Immigration Council's fact sheet.