To obtain a SSN, see Form SS-5, Application for a Social Security Card. To get Form SS-5 or to find out if you are eligible to obtain a SSN, contact a SSA office. By law, an alien individual cannot have both an ITIN and a SSN.
IRS processes returns showing SSNs or ITINs in the blanks where tax forms request SSNs. IRS no longer accepts, and will not process, forms showing "SSA", 205c", "applied for", "NRA",& blanks, etc.