If you pay contractors or vendors more than $600 in a calendar year, you need a W-9 on file before you can file the matching 1099. Sounds simple. In practice, W-9 collection is one of the most frustrating small tasks in finance: forms sent back half-filled, wrong TIN, missing signatures, PDFs stuck in someone’s inbox in December when you’re trying to close the year.
This guide walks through how to collect W-9 forms from vendors the right way — before you cut the first check, without chasing anyone at 1099 season, and with a paper trail you can defend if the IRS asks.
What is a W-9 form and why you need it
Form W-9 (Request for Taxpayer Identification Number and Certification) is a one-page IRS document that a US vendor uses to give you their legal name, business name, tax classification, address, and Taxpayer Identification Number (TIN) — either an SSN or an EIN. You use that information to report payments on Form 1099-NEC or 1099-MISC at year-end.
You need a W-9 whenever you pay a US person or entity — sole proprietor, LLC, partnership, or freelancer — $600 or more in a calendar year for services. You do not need one from most C corporations or S corporations, but it’s a good habit to request it from every vendor anyway. The extra minute at onboarding beats hunting the form down in January.
The consequence of skipping this step is not theoretical. If you can’t collect a TIN, the IRS requires 24% backup withholding on every payment to that vendor until you get one. That means your finance team either withholds a quarter of the invoice, or you eat the penalty. Neither is a good look.
When to collect a W-9 form
The best time to collect a W-9 is before you send the first payment — ideally at vendor onboarding, alongside the contract. Not:
- After the first invoice is approved
- At the end of the year when payroll is prepping 1099s
- After someone from accounts payable has emailed the vendor three times
Making W-9 collection a required step in your vendor onboarding checklist removes the annual scramble. Same principle for contractors: build it into your 1099 contractor onboarding checklist so no vendor ever enters your payables system without one on file.
Why W-9 collection goes wrong
Before we fix the process, it helps to name what usually breaks it:
- Email attachments get lost. The vendor emails the form to a general inbox. It sits in a shared mailbox no one owns. Six months later, no one can find it.
- Wrong version of the form. A vendor sends back a scanned copy of a 2015 W-9 they had lying around. The classification checkboxes changed. Now you have to ask again.
- Missing or wrong TIN. The vendor writes the wrong number of digits, or their SSN doesn’t match the name the IRS has on file. You only find out when your 1099 filing gets rejected.
- Unsigned or undated forms. The form is technically incomplete without a signature. Auditors will flag it.
- No renewal process. A vendor changes their legal structure from sole prop to LLC and their EIN changes. Nobody tells you. You keep filing 1099s under the old TIN.
Fixing these problems is less about the form itself and more about the process around it: how you request it, where you store it, and who owns the follow-up.
Step-by-step: how to collect W-9 forms from vendors
Here’s a repeatable process that works whether you have 5 vendors or 500.
Step 1: Add W-9 collection to your vendor onboarding
Every new vendor should complete a short intake that includes:
- W-9 upload (or fillable equivalent)
- Bank details for ACH
- A signed services agreement or MSA
- COI if the work involves being on your premises or handling client data
If you already have a structured vendor intake — see our vendor risk assessment checklist for the full list of items you might want to gather — the W-9 slots in as a required document. No W-9, no vendor record. No vendor record, no PO number.
Step 2: Send the request through a portal, not email
Do not attach a blank W-9 to an email and ask the vendor to fill it in. Every step of that flow is where forms go to die. Instead, send the vendor a link to a secure upload portal where they can:
- Download the current IRS W-9 (or fill in a digital equivalent)
- Upload the completed form
- See exactly what other documents you need
- Get automatic reminders if they don’t finish
A portal-based approach also gives you a single source of truth. The document lives with the vendor record, not scattered across inboxes. Same reasoning applies to any file you’re collecting from external parties — a real document upload portal beats email attachments every time.
Step 3: Validate the form on receipt
Before you file the form and pay the invoice, check:
- Line 1 (legal name) matches the entity on the invoice
- Line 3 (federal tax classification) is filled in
- Line 5 & 6 (address) is complete
- Part I has a valid TIN (SSN or EIN)
- Part II is signed and dated
A trained accounts payable clerk can do this in 30 seconds. But so can automated validation rules, and the machine never forgets to check.
Step 4: Store the form somewhere you can find it in three years
The IRS wants you to retain W-9s for at least four years after the last payment or the date the tax became due, whichever is later. That means you need durable, searchable storage — not a folder on someone’s laptop, not an inbox that gets purged.
Store the W-9 with the vendor record so any team member can find it. Tag it with a document type (W-9, W-8BEN, W-8BEN-E) so you can filter and audit. Restrict access to finance and compliance roles because the form contains an SSN or EIN.
Step 5: Set up a renewal trigger
W-9s technically don’t expire, but they need to be re-requested whenever any of the following changes:
- The vendor’s legal name
- The vendor’s TIN
- The vendor’s tax classification
- Ownership or structure of the business
Rather than polling every vendor every year, tag your vendor records with the date the current W-9 was received. When any change is flagged (new invoice from a different entity name, updated payment details, etc.), your process should require a fresh W-9 before the next payment clears. This is easier if your system supports document expiration tracking — you can set a review date and be reminded automatically instead of relying on memory.
Sample email requesting a W-9 form
If you’re still doing this over email, at least use a template that reduces back-and-forth. Here’s one that works:
Subject: Quick request before we process your first invoice — W-9 form
Hi [First name],
Welcome aboard. Before we can set you up in our payables system and process invoices, we need a completed IRS Form W-9 on file. This is standard for all US vendors we pay $600 or more per year.
The form is short — one page, takes about two minutes. You can download the latest version directly from the IRS here: https://www.irs.gov/pub/irs-pdf/fw9.pdf
Please complete it and reply to this email with the signed PDF attached. If you’d rather upload it through our secure vendor portal, use this link: [portal link]
Let me know if you have any questions.
Thanks,
[Your name]
For a more complete script — including the follow-ups you’ll inevitably need to send — see our guide on how to follow up on missing documents.
How to automate W-9 collection
Manual W-9 collection scales up to about 20 vendors before it becomes someone’s part-time job. Past that point, you want a system that:
- Triggers the request automatically when a new vendor is added to your CRM, procurement tool, or accounting system.
- Sends the vendor a branded portal link with clear instructions and the current W-9 form pre-attached.
- Chases the vendor for you with configurable reminders (day 3, day 7, day 14) until the form is uploaded.
- Validates the file on submission — was a PDF uploaded? Is it signed? Is the TIN the right length?
- Notifies your team the moment the W-9 is received and stored.
- Prompts for a renewal when any vendor detail changes.
That’s exactly the shape of workflow Superdocu is built for. You define the vendor intake once (W-9 + banking details + MSA + COI + anything else you need), and every new vendor gets guided through it. If they don’t finish, automated reminders keep going until they do. If you’re evaluating tools for this, take a look at our overview of document collection apps to see how automated collection compares to what you’re doing today.
W-9 vs W-8: quick note on foreign vendors
If your vendor is not a US person, they should not fill out a W-9. Instead, you need one of the W-8 series:
- W-8BEN — Non-US individuals (foreign freelancers)
- W-8BEN-E — Non-US entities (foreign companies)
- W-8ECI — Foreign entity claiming income is effectively connected to a US trade
Payment to foreign vendors triggers different withholding rules (often 30%, sometimes reduced by tax treaty). A good vendor onboarding process asks the right form at the right time based on the vendor’s country of residence — don’t assume every contractor is a US person.
Storing and protecting W-9 data
A completed W-9 contains a legal name and a TIN — enough to enable identity fraud if it leaks. Handle W-9 documents like any other sensitive record:
- Store them in an access-controlled system, not a shared drive
- Encrypt at rest and in transit
- Restrict access to finance, compliance, and audit roles
- Log who viewed or downloaded each file
- Delete or archive after the required retention period
If you’re consolidating from email attachments and shared folders to something more auditable, the general principles in our guide to secure file sharing solutions apply here too.
Frequently asked questions
Do I need a W-9 from every vendor?
You need one from every US person or entity you pay $600 or more per year for services. Corporations are generally exempt from 1099 reporting, but it’s still best practice to request a W-9 from every vendor so you have documentation of their tax status on file.
Can I accept a W-9 by email?
Yes — the IRS does not require any specific delivery method. Email works legally, but it’s not ideal operationally. Email attachments get lost, versions get confused, and the data ends up scattered across inboxes. A vendor portal keeps everything in one place and reduces manual follow-up.
What happens if a vendor refuses to provide a W-9?
You are required to begin backup withholding at 24% on every payment to that vendor until you receive a valid W-9. You send the withheld amount to the IRS and report it on Form 945.
How long do I need to keep W-9 forms?
The IRS requires you to retain W-9 forms for at least four years after the last payment to the vendor or the date the tax became due, whichever is later. Most companies keep them indefinitely as part of the vendor record.
Do W-9 forms expire?
W-9 forms do not have a formal expiration date. However, you should request a new one whenever the vendor’s legal name, TIN, tax classification, or business structure changes.
Can I use an electronic W-9?
Yes. The IRS accepts electronic W-9s as long as the system captures the required certification, records who signed it and when, and provides a hard copy on request. A signed PDF uploaded through a secure portal meets these requirements.
Ready to stop chasing W-9s?
If W-9 collection currently means an accounts payable person emailing vendors, tracking replies in a spreadsheet, and scrambling every December — there’s a better way.
Superdocu lets you build a vendor intake workflow once, invite each new vendor to complete it, and get notified when their W-9 (and every other document you need) is uploaded, validated, and stored against their record. Automated reminders handle the follow-up. Expiration tracking handles the renewals.