An SSN is an identification number issued by the Social Security Administration (SSA) and is intended for U.S. citizens, permanent residents, and foreign workers authorized to work in the U.S. This number is required to work legally, pay taxes, and access certain government benefits.

An ITIN, on the other hand, is an individual taxpayer identification number issued by the Internal Revenue Service (IRS) and is intended for people who are not eligible for an SSN, such as undocumented immigrants or temporary residents. While it does not allow them to work legally in the U.S., it enables these individuals to meet their tax obligations and access some financial services, like building a credit history.