Like Social Security numbers, the ITIN is also nine digits in length. On the off chance that you're a qualifying non-resident or a resident outsider (green card holder), you, your spouse, and your dependents can get an ITIN.

Any individual who earns pay from the U.S. is required to get a tax ID number, since they're committed to pay taxes on what they procure.

Beginning with your ITIN number
There are three ways you can apply for an ITIN:

Go through an IRS-authorized Ensuring Acknowledgment Agent (CAA). These services are accessible both inside and outside the U.S. As a rule, you must make an arrangement. Carry unique documents to demonstrate your qualification.
Apply at a designated IRS Taxpayer Assistance Center. The IRS requires you to make an arrangement and provide unique documents demonstrating your qualification.
Mail an application: The IRS allows you to apply for an ITIN at the same time you document your taxes. To do as such, you submit a W-7 form and complete a tax return. You'll also have to provide unique or confirmed copies of documents demonstrating your identity and unfamiliar status.
When you accept your ITIN, you'll have the option to use it to record taxes from now on.

Documents for the ITIN application
Regardless of how you choose to apply for an ITIN, the IRS will ask you to provide something like two types of documents:

Proof of identity
Proof of your outside identity or U.S. residency status
What counts as proof of identity for the IRS?
Passport (this can demonstrate both your identity and residency status)
A U.S. Division of State-issued visa
U.S. driver's license
Personal ID issued by U.S. Citizenship and Migration Services (USCIS)
U.S. military identification card
Unfamiliar driver's license
Unfamiliar military identification card
U.S. state identification card
Unfamiliar common birth declaration
Unfamiliar clinical records (for dependents under six years old)
Public ID card with your name, address, date of birth, photograph, and termination date
Unfamiliar citizen's registration card
Unfamiliar school records (for dependents who are students and under 18 years old)