If you have earned an income, recieved a taxable scholarship, or if your country has an income tax treaty, you must file the proper tax return(s) with the IRS. More information and answers to your tax-related questions are here. International Student Services cannot help you with your taxes.
If you do not have a social security number and cannot be issued one, you must apply for an individual taxpayer identification number, or ITIN. Apply for one using the Form W-7 and return it with your tax return(s) and Form 8843.
Pay attention to IRS deadlines to make sure you do not file too late.