Form W-7 is the IRS application used to request an individual taxpayer identification number when a Social Security number is not available.
Form W-7 is the IRS application used to request an individual taxpayer identification number, or ITIN, when a Social Security number is not available. In plain language, it is the form people use to apply for the taxpayer-identification number needed for certain federal tax filings and reporting situations.
Form W-7 matters because many federal tax workflows begin with identity and number validation before the return itself can be filed correctly. If a taxpayer or dependent does not have an SSN, the tax process can still require a valid IRS identification number.
It also matters because readers often confuse the application form with the number itself. The ITIN is the identifier. Form W-7 is the application used to request it.
Form W-7 appears before or alongside return filing when an ITIN is required for a taxpayer, spouse, or dependent. The taxpayer uses Form W-7 to apply for the identifier, then uses that number in the return and related reporting documents once issued.
A taxpayer needs to file a federal return that requires an identifying number for a spouse or dependent who does not qualify for an SSN. The taxpayer uses Form W-7 to apply for an ITIN so the return can be processed correctly.
Form W-7 is not the same as an Individual Taxpayer Identification Number. One is the application form; the other is the number issued by the IRS.
It is also different from Form W-9, which requests existing taxpayer information from a payee rather than applying for a new IRS identification number.