Fill out taxpayer identification forms
with AI.
Taxpayer identification forms are IRS documents used to collect and certify the tax identification numbers of individuals and businesses. These forms play a critical role in the U.S. tax system, ensuring that income payments are properly reported to the IRS and that the correct parties are held accountable for their tax obligations. The most widely recognized form in this category is the W-9, which is used to provide a Taxpayer Identification Number (TIN) — whether that's a Social Security Number, Individual Taxpayer Identification Number, or Employer Identification Number — to payers who must file information returns.
By continuing, you acknowledge Instafill's Privacy Policy and agree to get occasional product update and promotional emails.
About taxpayer identification forms
Anyone who works as a freelancer, independent contractor, or self-employed professional will likely encounter these forms regularly. Businesses also request them from vendors, consultants, and service providers before issuing payments. Providing accurate information on these forms is important: an incorrect or missing TIN can trigger a 24% backup withholding on payments, which can be a costly and frustrating outcome for both parties.
For people who need to complete these forms quickly and correctly, tools like Instafill.ai use AI to fill them out in under 30 seconds, reducing the risk of errors and keeping your information secure. Whether you're filling out a W-9 for a new client or updating your certification details, having a reliable and efficient way to handle these documents makes the process significantly less time-consuming.
Forms in This Category
- Enterprise-grade security & data encryption
- 99%+ accuracy powered by AI
- 1,000+ forms from all industries
- Complete forms in under 60 seconds
How to Choose the Right Form
Both forms in this category serve the same core purpose — collecting your Taxpayer Identification Number (TIN) for IRS reporting — but here's how to quickly decide which version to use.
If You Need the Standard W-9
Both W-9, Request for Taxpayer Identification Number and Certification and Form W-9, Request for Taxpayer Identification Number and Certification are versions of the same IRS document. You'll need one if:
- You're an independent contractor or freelancer who has been asked by a client to provide your TIN
- You're a business owner collecting TIN information from vendors or contractors
- You need to avoid backup withholding (currently 24%) on payments like freelance income, interest, or dividends
- You're involved in real estate transactions or receive dividend/interest payments
Which Listing Should You Choose?
- The first listing (W-9) is a great starting point for contractors, freelancers, and business owners who need a straightforward, familiar version of the form.
- The second listing (Form W-9) provides additional detail on use cases — including certifying SSNs, ITINs, or EINs — and highlights AI-assisted filling via Instafill.ai, which is especially helpful if you have a non-fillable PDF version.
Quick Tips
- Not sure which TIN to use? Use your SSN if you're an individual, your ITIN if you're a non-resident alien, or your EIN if you're a business entity.
- Received a request from a payer? Either form version will produce the same valid, IRS-compliant W-9.
- Working with a scanned or non-fillable PDF? The second listing specifically supports AI-powered conversion and completion.
In short, both forms lead to the same result — pick the one whose description best matches your situation and fill it out online using Instafill.ai.
Form Comparison
| Form | Purpose | Who Files It | When to Use |
|---|---|---|---|
| W-9, Request for Taxpayer Identification Number and Certification | Provide TIN and certification for tax reporting | Independent contractors, freelancers, business owners | When payer requests TIN for income reporting |
| Form W-9, Request for Taxpayer Identification Number and Certification | Certify TIN and U.S. person status to avoid backup withholding | Individuals and entities receiving reportable payments | Before receiving interest, dividends, or freelance payments |
Tips for taxpayer identification forms
A single digit error in your Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Employer Identification Number (EIN) can trigger IRS backup withholding of 24% on your payments. Always verify your TIN against an official document — such as your Social Security card or IRS EIN confirmation letter — before handing the form to a requester. Correcting a TIN mismatch after the fact can be time-consuming and may delay your payments.
One of the most common mistakes on taxpayer identification forms is choosing the wrong federal tax classification — for example, marking 'Individual/Sole Proprietor' when you operate as a single-member LLC. Your classification affects how the requester reports payments to the IRS, so it must accurately reflect your legal business structure. If you're unsure which box applies to you, consult the IRS instructions or a tax professional before submitting.
AI-powered tools like Instafill.ai can fill out taxpayer identification forms like the W-9 with high accuracy in under 30 seconds, saving you significant time — especially if you're submitting to multiple clients or payers. Your data stays secure throughout the process, making it a trustworthy option for sensitive tax information. It's a practical solution for freelancers and contractors who regularly need to provide W-9s to new clients.
You should provide an updated taxpayer identification form whenever your information changes — such as a legal name change, a new EIN after restructuring your business, or a change in tax classification. Requesters may also ask for a new form periodically to keep their records current. Proactively updating your information helps avoid payment delays and potential backup withholding issues.
An unsigned W-9 is considered invalid and will typically be returned to you by the requester, delaying your payments. The signature certifies that your TIN is correct and that you are not subject to backup withholding (or that you are exempt), so it carries legal weight. Always sign and date the form before submitting, even when sending it electronically.
Save a copy of each completed taxpayer identification form you send to clients, financial institutions, or other requesters. This creates a paper trail that can be invaluable if there's ever a dispute about your reported information or if you need to reference past submissions at tax time. Organizing these copies by client name and date makes retrieval fast and straightforward.
The W-9 includes fields for 'Exempt payee code' and 'Exemption from FATCA reporting code,' which apply to specific entities like corporations or tax-exempt organizations — not to most individual freelancers or sole proprietors. Incorrectly claiming an exemption can create compliance issues with the IRS and your payers. Only fill in these fields if you are certain your entity qualifies, and reference the official IRS instructions to confirm.
Taxpayer identification forms contain your SSN or EIN, which are prime targets for identity theft. Avoid sending completed forms via unencrypted email or leaving physical copies unsecured. Use secure file-sharing methods, and only provide the form to verified, legitimate requesters who have a legal need for your tax information.
Frequently Asked Questions
Taxpayer identification forms are used to collect and certify a person's or business's taxpayer identification number (TIN) for tax reporting purposes. They help payers — such as businesses, banks, and financial institutions — accurately report payments to the IRS and avoid backup withholding on those payments.
This category includes versions of the IRS Form W-9, Request for Taxpayer Identification Number and Certification. The W-9 is the primary IRS form used to provide your TIN — whether that's a Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Employer Identification Number (EIN) — to a requester.
Anyone who receives payments that require IRS reporting may need to complete a taxpayer identification form. This commonly includes independent contractors, freelancers, self-employed individuals, sole proprietors, partnerships, corporations, and other entities that receive income such as freelance pay, interest, dividends, or real estate proceeds.
You'll typically be asked to complete a taxpayer identification form before you receive your first payment from a new client, employer, or financial institution. Businesses and payers are required to collect this information before filing information returns (such as a 1099) with the IRS, so requests often come at the start of a new working relationship.
Backup withholding is a tax withholding mechanism where a payer withholds a percentage — currently 24% — from certain payments when a payee has not provided a correct TIN or has been notified by the IRS of underreporting. By completing a taxpayer identification form accurately and promptly, you certify your TIN and confirm your status, which helps prevent backup withholding from being applied to your payments.
No — taxpayer identification forms like the W-9 are not sent to the IRS by the individual completing them. Instead, you provide the completed form to the requester (such as a client, employer, or financial institution), who then uses the information to file the appropriate information returns with the IRS on your behalf.
Taxpayer identification forms accept several types of TINs depending on your situation. Individuals typically use a Social Security Number (SSN) or an Individual Taxpayer Identification Number (ITIN), while businesses and other entities generally use an Employer Identification Number (EIN).
Yes — AI-powered tools like Instafill.ai can fill out taxpayer identification forms like the W-9 in under 30 seconds by accurately extracting and placing your information from source documents. These tools can also convert non-fillable PDF versions into interactive fillable forms, making the process faster and reducing the risk of errors.
Manually filling out a taxpayer identification form typically takes just a few minutes since the information required — such as your name, address, and TIN — is straightforward. With AI-assisted tools like Instafill.ai, the process can be completed in under 30 seconds by automatically populating the form fields from your existing documents.
No — taxpayer identification forms like the W-9 are not tax returns. They are informational forms used to certify your TIN and provide it to a payer or requester. Tax returns are separate documents filed directly with the IRS to report your income and calculate any taxes owed or refunds due.
You generally only need to submit a taxpayer identification form once per payer or requester, unless your information changes — such as a new name, address, or TIN. If a new client or financial institution requests your information, you'll need to provide a fresh form for that relationship.
The requester who receives your completed taxpayer identification form is legally obligated to keep your information confidential and use it only for tax reporting purposes. However, since these forms contain sensitive information like your SSN or EIN, it's important to only provide them to trusted and verified requesters.
Glossary
- TIN (Taxpayer Identification Number)
- A unique number assigned by the IRS to identify individuals or businesses for tax purposes. It can be a Social Security Number (SSN), Employer Identification Number (EIN), or Individual Taxpayer Identification Number (ITIN).
- Backup Withholding
- A mandatory tax withholding of 24% that payers must deduct from certain payments when a payee fails to provide a correct TIN or is flagged by the IRS. Completing a W-9 accurately helps you avoid this automatic deduction.
- EIN (Employer Identification Number)
- A nine-digit number assigned by the IRS to businesses, partnerships, and other entities for tax identification purposes. It is used on a W-9 in place of an SSN when the filer is a business rather than an individual.
- ITIN (Individual Taxpayer Identification Number)
- A tax processing number issued by the IRS to individuals who are not eligible for a Social Security Number, such as certain foreign nationals. It can be used as a TIN on Form W-9.
- Information Return
- A tax document that payers (such as businesses or financial institutions) file with the IRS to report payments made to others, such as a 1099 form. The W-9 provides the information needed to prepare these returns.
- U.S. Person
- A classification for tax purposes that includes U.S. citizens, resident aliens, domestic partnerships, corporations, and certain other entities. Certifying U.S. person status on a W-9 determines how the IRS taxes your income.
- Requester
- The individual or organization (such as a client, bank, or employer) who asks you to complete a W-9 so they can report payments made to you to the IRS.
- Federal Tax Classification
- A category on Form W-9 where you identify your business structure, such as individual/sole proprietor, LLC, C corporation, S corporation, or partnership. Your classification affects how your income is taxed and reported.
- Exempt Payee Code
- A code entered on Form W-9 by certain entities (such as corporations or tax-exempt organizations) that are not subject to backup withholding. Most individuals and sole proprietors leave this field blank.