Your tax id is....
in most cases your SSN. If you do not have an SSN - you can file for an ITIN If you have a business or a single member LLC - an EIN is what you need. This is said on ITIN: If you do not have an SSN and are not eligible to obtain an SSN, but you have a requirement to furnish a federal tax identification number or file a federal income tax return, you must apply for an ITIN. By law, an alien individual cannot have both an ITIN and an 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 "SSA205c," "applied for," "NRA," blanks, etc. Enjoy your tax....