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Home > Guides > Faxing a W-9 form
Yes, you can fax a W-9 form, and many payers still accept it that way, but a W-9 carries your taxpayer identification number, so the number you fax to and the copy you keep matter more than the method. Confirm the payer fax number from a trusted source, send only the completed form, and keep the confirmation page as proof you sent it.
This is general information, not tax advice.
A W-9 gives a payer your legal name, business name if you have one, federal tax classification, address, and taxpayer identification number, which for most individuals is a Social Security number. The payer uses it to report payments to the tax authority and to decide whether backup withholding applies. That combination makes a W-9 a prime target for identity theft: with a name, address, and taxpayer number, a thief can open accounts or file false returns. Treat a W-9 like a signed check, not like a routine form.
One non-obvious point: a W-9 is not filed with the tax authority. It goes to the payer, who keeps it on file and uses it when reporting. Sending it to the wrong office, or to a payer you do not actually work for, creates a record in the wrong hands with no benefit to you. If a requester asks for a W-9 out of the blue, verify the request before sending anything.
Start by confirming the fax number independently. Do not trust a number printed in an unsolicited email alone; check the payer website, a contract, or a phone call to a known number. Use a cover sheet that names the recipient and the document, but do not repeat the taxpayer number on the cover sheet: the number belongs on the form itself, not on a page that might sit on a shared machine. Send only the pages the payer asked for, and avoid adding extra pages with other personal details.
After sending, keep the confirmation page and note the date, the number you sent to, and the name of the person who requested the form. If the payer later says the form never arrived, that note is what lets you resend without re-exposing the number to a second, unverified address. If you suspect you faxed to the wrong number, tell the payer at once and watch for signs of identity misuse, such as unexpected tax documents or account notices.
| Step | What to do |
|---|---|
| Verify the request | Confirm the payer actually needs a W-9 and that the request came from them. |
| Confirm the number | Check the fax number against the payer site, contract, or a known phone number. |
| Complete the form | Fill in every required field, sign and date it, and check the number twice. |
| Use a cover sheet | Name the recipient and document, without repeating the taxpayer number. |
| Keep proof | File the confirmation page with the date and number sent. |
For this form, fax usually beats ordinary email. An unencrypted email attachment can be copied at every server it passes through and forwarded by mistake, while a fax goes to one number and produces a confirmation record. That comparison only holds if the receiving machine is not shared: a fax sitting in an open office tray is no safer than an email in a shared inbox. If the payer offers a secure portal upload, that is generally the best option of all, since access is logged and the file is encrypted in transit. Fax sits in the middle: better than plain email, weaker than a proper portal.
In Canada, the parallel form is different: payers generally ask for a TD1 or a business number record rather than a W-9, and a W-9 is mainly a US form used when a Canadian business or individual is paid by a US payer. If a Canadian payer asks for a W-9, ask why, since the answer may be that they report to the US tax authority for that payment.
Yes, for US and Canadian fax numbers. You ask your AI assistant, get a per-fax quote with the page count verified, approve the exact total, and pay once through Stripe. Fax is currently in testing, so it is described as available in testing and a fax is never promised to send on a particular day. Check the payer number twice before approving, because a W-9 sent to the wrong number cannot be recalled.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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