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Last updated September 3, 2026
Use a Certifying Acceptance Agent when you want help preparing Form W-7 and do not want to mail your original passport to the IRS. Direct mail costs no IRS fee but can require original or issuing-agency-certified documents. An IRS Taxpayer Assistance Center is free and can authenticate most documents, but it requires a suitable U.S. appointment.
For non-residents applying from abroad, the practical decision often comes down to passport control, travel, appointment access, and how much application help is needed.
ITIN application routes compared
| Decision factor | Certifying Acceptance Agent | Direct mail to IRS | IRS Taxpayer Assistance Center |
|---|---|---|---|
| IRS fee | $0; agent charges professional fee | $0 | $0 |
| Form W-7 help | Included within agreed agent scope | Self-prepared or separate adviser | IRS says TAC reviews but does not complete W-7 for you |
| Identity documents | CAA authenticates most permitted documents | Original or issuing-agency-certified copies generally submitted | Most documents authenticated and returned at appointment |
| Location | U.S. and international agents | Anywhere with reliable delivery | U.S. locations offering ITIN services |
| Scheduling | Depends on agent | No appointment | Appointment and travel required |
| IRS decision speed | Normal IRS queue | Normal IRS queue | Normal IRS queue |
The IRS application-route comparison also lists participating VITA sites, which may provide free help at limited U.S. locations.
What a CAA actually does
A CAA is not an employee of the IRS and cannot approve an ITIN. Under the IRS Acceptance Agent program, a CAA can help complete Form W-7, authenticate most supporting documents, return authenticated documents immediately, mail the application package, and work with the IRS on application issues.
Some items have authentication limits. Foreign military identification and certain dependent documents fall outside a CAA’s normal authentication authority. The applicant may still need original or issuing-agency-certified evidence for those items.
Form5472 Prep’s ITIN service costs $349 and includes W-7 preparation plus CAA certification. It is designed for applicants who have a valid federal tax purpose and want the original passport to remain with them.
When direct IRS mail makes sense
Direct mail can be the lowest cash-cost route when you:
- understand the W-7 reason and instructions;
- have the attached federal return or complete exception evidence;
- can obtain the required certified documents;
- accept the shipping and document-return process; and
- can manage any IRS correspondence yourself.
Use tracked delivery and keep a complete copy. The IRS tells applicants to contact it if mailed original documents have not been returned within 60 days. Consider the practical effect of being without a passport before choosing to send the original.
When a Taxpayer Assistance Center makes sense
A TAC with ITIN services is attractive when you can attend in the United States and obtain an appointment. The service is free, the TAC reviews Form W-7, and most supporting documents can be authenticated and returned.
The tradeoff is that not every office offers ITIN authentication, appointments can be limited, and the TAC does not complete Form W-7 for you. Verify the specific location and bring the entire application package.
Do all routes require a tax return?
Usually, a new ITIN application includes Form 1040 or Form 1040-NR. The route used to authenticate documents does not remove that requirement. A return can be omitted only when the applicant fits an exception in the Form W-7 instructions and includes the specified evidence.
That distinction is central to choosing a provider. Ask whether the quoted service includes the attached tax return or only the W-7 and identity certification.
A simple decision rule
- Choose direct mail for the lowest professional cost when you can prepare and control the complete package.
- Choose a TAC when you can attend a U.S. appointment and mainly need document authentication.
- Choose a CAA when you want preparation support and passport-safe authentication without relying on a U.S. appointment.
Start with Form5472 Prep’s CAA service for a $349 flat fee. Confirm the federal tax purpose first; the service cannot create eligibility where none exists.
Application routes and price checked September 3, 2026. Educational information only; not tax or legal advice.