ssn is used for tax returns, and ssn can be used to apply for credit cards. With SSN, others can track your credit history.

For example, if you want to apply for chase's credit card, you need to fill out an application, which requires SSN. With your SSN, your bank can check your credit history, and if your record is not good, it will not be approved. When you rent a house in the United States, especially in new york, your credit history is particularly important. Without it, others may not rent the house to you. And if you don't have ssn, you can't establish any credit history. By the way, you can't work in the United States without ssn.

As for how to apply for ssn, the easiest way is to apply for a green card, and you can do it naturally when you get a green card.

The second easiest way to do ssn is to work in a school. You can apply for ssn with your passport I2 and the signature of iss. You can also apply for opt after graduation, and use opt to do SSN.

As for non-students.