After reviewing a CP2000 notice and deciding how to respond, many taxpayers want to know whether they can submit their response online through the IRS website or whether mail is the only option.

The short answer is that for most taxpayers, mail remains the standard and most reliable method, though limited online options exist in specific circumstances. Understanding the differences between these methods – and what each requires – will help you submit a complete, timely, and properly documented response.

The Standard Method: Responding by Mail

The primary response method for a CP2000 is written correspondence sent by mail to the address printed on the notice. This has been the standard procedure for the Automated Underreporter program and remains the method the IRS prepares for when it issues a CP2000.

Why Mail Is the Default

The CP2000 response process requires you to submit a signed response form along with supporting documentation. The signed form indicates your agreement, partial agreement, or disagreement with the proposed changes. Supporting documentation – which may include Forms 1099, brokerage statements, bank records, or written explanations – must accompany the form.

These requirements make mail the most practical submission method. Unlike a simple online form, a CP2000 response is a document package that typically includes multiple pages of records. The IRS scanning and processing systems are equipped to handle mailed responses with attachments in a way that most current online portals are not.

What to Send

Your mailed response should include:

• The completed response form attached to the CP2000, signed and dated
• A written explanation for any items you are disputing, stating your position clearly and identifying the specific items by line reference
• Copies of all supporting documents (not originals – the IRS does not return documents)
• The payment voucher and any payment, if you are agreeing and paying the proposed amount
• Form 9465 (Installment Agreement Request) if you agree with the tax owed but cannot pay the full amount immediately

Where to Send It

Always mail to the address printed on your specific CP2000 notice. IRS notices include response addresses that route to the campus handling your account. Do not send to a generic IRS address. Misdirected responses cause processing delays and may result in the notice proceeding past the response window before your reply reaches the correct campus.

Use Certified Mail

Send all responses via USPS certified mail with return receipt requested. This provides a timestamped record of the mailing date, which is the date that counts for deadline purposes. Retain the tracking number, the return receipt, and a copy of everything in your response package.

Private delivery services that are IRS-designated – including UPS and FedEx – also provide a legally recognized postmark date and can be used as an alternative to USPS certified mail. If you use a private service, be certain to confirm the delivery address accepts private carriers, as some IRS campus P.O. boxes do not.

Responding Online: What the IRS Currently Offers

The IRS has expanded its online services in recent years, but as of this writing, the ability to submit a full CP2000 response through IRS.gov is limited. Most taxpayers cannot submit a CP2000 response, with supporting documentation, entirely online.

IRS Online Account

Taxpayers can access an IRS online account at IRS.gov, which allows them to:

• View notices and letters, including some CP2000 notices, for certain account types
• Make payments toward any proposed or assessed balance
• View payment history and balance details
• Access transcripts of prior year returns

However, the online account does not currently include a portal for submitting CP2000 response forms with attachments for most individual filers. You can use the account to pay a balance if you agree with the proposed changes, but the signed response form should still be mailed separately to confirm your agreement.

IRS Free File and Tax Software

If the discrepancy involves a correction to your original return – for example, if you agree that income was underreported and want to file an amended return rather than simply agreeing with the CP2000 – you can file Form 1040-X through IRS Free File or tax software platforms. Since 2020, the IRS has accepted electronically filed amended returns for most individual filers.

However, filing an amended return is not the same as responding to the CP2000. The IRS instructs taxpayers not to amend their return solely in response to a CP2000, unless the notice specifically instructs them to do so. Responding with an amendment instead of a CP2000 response form can create processing confusion. In most cases, the correct approach is to respond directly to the CP2000 using the attached form and then, if appropriate, file an amended return afterward.

IRS.gov and CP2000 FAQ Resources

The IRS maintains information about the CP2000 process at IRS.gov, including instructions on how to respond and general guidance on the Automated Underreporter program. This is useful for reference but does not constitute a submission mechanism. Visiting IRS.gov does not constitute a response to your notice.

Calling the IRS: The Phone Option

While not a substitute for a written response, the IRS phone line listed on the CP2000 notice serves several purposes:

• You can call to request an extension of the response deadline if you cannot respond within 60 days
• You can ask clarifying questions about specific items in the notice before preparing your response
• If you agree with all proposed changes and the balance is small, in some cases an IRS representative may be able to process your agreement over the phone – though you should still confirm the outcome in writing

The phone number for CP2000 inquiries is printed on the notice. IRS call centers handle high volumes of calls, and wait times can be long. Call early in the day and early in the week for shorter waits. When you call, have your notice and Social Security number ready, along with any documents you plan to reference.

Important: a phone call does not substitute for a written response when you are disputing items or providing supporting documentation. The IRS cannot process documentation over the phone. Even if you discuss your position with an IRS representative, follow up with a written response and copies of your documentation by the deadline.

Required Documents for Any Response Method

Regardless of whether you respond by mail, supplement with a phone call, or use any online tools available, the required documentation is the same. Your response must address every item listed in the CP2000 notice.

For Agreement

• Signed response form (check the agree box)
• Payment or Form 9465 if you cannot pay in full

For Disagreement or Partial Disagreement

• Signed response form (check the disagree box)
• Written explanation identifying each disputed item
• Copies of income statements (W-2, 1099 forms) showing the correct figures
• Brokerage records showing cost basis and purchase date for investment-related discrepancies
• Form 8606 for IRA basis claims
• Documentation of rollover transactions within 60 days for retirement distribution disputes
• Any corrected forms issued by the payer after your original return was filed
• Proof that income was reported in a different location on your return (attach the relevant schedule from your return)

Submission Tips for a Cleaner Process

Whether responding by mail or using any supplemental online or phone tools available, the following practices improve the odds of a smooth resolution:

• Label every document you attach. Include a cover sheet that lists each attachment and what it relates to in the notice.
• Reference specific items from the notice in your written explanation. Use the IRS line references where possible.
• Respond to every item listed in the notice, even items you agree with. A response that addresses only disputed items and is silent on others may cause the IRS to treat the unanswered items as agreed.
• Keep the response organized chronologically or by item, not as a single block of text. Examiners process many responses and clear organization speeds up review.
• Include a cover letter identifying the notice number, your Social Security number, and the tax year in question.

For Guidance on What to Include in Your Response

For a step-by-step guide to preparing a complete CP2000 response package, see our article on the first 5 steps to respond to a CP2000.

If you are unsure whether you have enough time to complete your response, our article on the CP2000 response deadline explains the 60-day window, extension options, and what happens at each stage if the deadline passes.

Summary

Most CP2000 responses must be submitted by mail using the form and address included in the notice. Limited online tools at IRS.gov allow you to view your account and make payments, but they do not support full CP2000 response submissions with documentation for most taxpayers. Certified mail remains the safest submission method because it preserves a verifiable record of the postmark date. Always keep a complete copy of your entire response package before mailing.