The original purpose of an SSN was to track an individual's tax status, but its use has now expanded to include personal identification, similar to the function of a 'Resident Identity Card Number' in China. The Social Security Number serves as a 'U.S. national ID.' It is valid nationwide and belongs to the individual.
Prerequisites for applying for a Social Security Number:
Step 1: You must have an immigration status. B1/B2, F1, and other visas do not qualify for a Social Security Number; you must first file Form I-485.
Form I-485: The application form used to adjust status to obtain a Green Card, which is considered the final step before receiving permanent residency.
Step 2: Obtain an Employment Authorization Document (EAD). After filing Form I-485, you can receive a Work Permit and have Employment Authorization, which is required before you can apply for a Social Security Number at the Social Security Administration.
EAD: The U.S. Employment Authorization Document (EAD card, also known as a work permit) is a card issued by the U.S. Citizenship and Immigration Services (USCIS) that authorizes a foreign national to work in the United States for a specific period (usually one year).
Methods for applying for a Social Security Number:
Method 1: Apply for a Social Security Number simultaneously when applying for an EAD card. The Social Security Number is a 9-digit number and cannot be self-selected.
Method 2: Apply in person at the Social Security Administration office with your passport and EAD card.
You must apply at the Social Security Administration office corresponding to your residential address.
In some states, an EAD card is not required to apply for a Social Security Number; for example, in some Midwestern states, you can obtain one through OPT.
OPT: Optional Practical Training refers to a period of work authorization for F1 visa holders (undergraduate, master's, and doctoral students) who, after completing at least nine months of study, are approved by the U.S. Citizenship and Immigration Services (USCIS) to engage in practical training in their field of study.
Some Social Security Numbers are marked as 'not valid for employment.' A Social Security Number belongs to the individual for life; regardless of whether you remain in the U.S. or what your status is in the future, having a Social Security Number can make life in the United States more convenient.