What is IRS (Internal Revenue Service)?

How it works

The IRS is the bureau of the US Department of the Treasury responsible for collecting federal taxes and enforcing the Internal Revenue Code. It is divided into operating divisions by taxpayer type:

• Wage and Investment (W&I) — individuals filing Form 1040.
• Small Business / Self-Employed (SB/SE) — Schedule C filers, small partnerships, sole proprietorships.
• Large Business and International (LB&I) — corporations with $10M+ assets, complex international filings.
• Tax-Exempt and Government Entities (TE/GE) — non-profits, retirement plans, government bodies.

The IRS does not make tax law — Congress does. It does not sign tax treaties — the Treasury and the State Department do. What the IRS does is issue regulations (with the Treasury), publish forms and instructions, process returns, audit, and collect.

Where the IRS interacts with non-residents

A non-resident with no US connection never deals with the IRS. The moment any of the following happens, they show up on the IRS's radar:

• Forming a US LLC → file Form SS-4 to get an EIN.
• Earning US-source FDAP (dividends, interest, royalties) → US payer issues Form 1042-S; the recipient files Form 1040-NR if reclaiming over-withheld tax.
• Earning US-source ECI (Effectively Connected Income) → file Form 1040-NR on graduated rates.
• Selling US real estate → FIRPTA withholding via Form 8288, then 1040-NR.
• Owning a foreign-owned single-member LLC → Form 5472 every year.
• Claiming treaty benefits → file W-8BEN (individuals) or W-8BEN-E (entities) with the US payer; sometimes Form 8833 with the IRS.
• Applying for an ITIN → file Form W-7.

The Form 1040-NR for non-residents is processed at the Austin, Texas service center; corporate filings go to Ogden, Utah; ITIN applications go to a dedicated unit also in Austin.

What the IRS doesn't do

• Beneficial Ownership Information (BOI) reports under the Corporate Transparency Act → that's FinCEN, not IRS.
• State tax — California, New York, Texas etc. each have their own state revenue authority.
• Customs and import — that's CBP (Customs and Border Protection), not IRS.
• Social Security claims → that's the SSA (Social Security Administration). The IRS just processes payroll-tax deposits that fund the program.

Examples

• French founder forms a Delaware LLC. First IRS contact: Form SS-4 fax to obtain an EIN. Annual IRS contact: Form 5472 + pro-forma 1120 mailed to Ogden, Utah.
• Brazilian investor sells $800,000 Miami condo. Buyer remits 15% FIRPTA withholding ($120,000) to the IRS via Form 8288. The investor files Form 1040-NR the following spring to compute actual tax on the gain and claim a refund of the over-withheld portion.

Common mistakes

• Confusing IRS with Treasury or FinCEN. Three different agencies, three different filing systems. Beneficial-ownership reports go to FinCEN, not the IRS — sending them to the IRS won't satisfy the Corporate Transparency Act.
• Trying to use the online IRS portal as a non-resident. Most online services require an SSN-linked identity verification. Plan for fax + mail workflows.
• Treating IRS guidance as law. IRS Notices, Revenue Rulings, and Publications are interpretive. Tax law is in the Internal Revenue Code (statute) and Treasury Regulations. Reasonable disagreement with IRS positions is sometimes the right answer.
• Calling the wrong IRS line. International phone support is limited to specific hours and dedicated lines — the toll-free domestic line won't help non-residents.