Identifying number. If you are an
individual, you are generally required to
enter your social security number
(SSN). To apply for an SSN, fill in
Form SS-5 and return it to the Social
Security Administration (SSA). You can
get Form SS-5 on line at
www.socialsecurity.gov, from your local
SSA office, or if in the United States, by
calling the SSA at 1-800-772-1213. It
usually takes about 2 weeks to get an
SSN.
    If you do not have and are not
eligible to get an SSN, you must apply
for an individual taxpayer identification
number (ITIN). For details on how to do
so, see Form W-7 and its instructions. It
usually takes about 4-6 weeks to get an
ITIN.
   If you already have an ITIN, enter it
wherever your SSN is requested on
your tax return. If you are required to
include another person’s SSN on your
return and that person does not have
and cannot get an SSN, enter that
person’s ITIN.
Note. An ITIN is for tax use only. It
does not entitle you to social security
benefits or change your employment or
immigration status under U.S. law.
   If you are filing Form 1040NR for an
estate or trust, enter the employer
identification number of the estate or
trust.
   An incorrect or missing identifying
number may increase your tax or
reduce your refund.