LetterAgent
Mail physical letters by just asking your AI assistant.
Home > Guides > Faxing tax documents to your accountant
Yes. Faxing tax paperwork to your CPA is a tax-season norm: accounting firms keep dedicated fax lines precisely for client returns and source documents. Accountants prefer fax over email attachments for sensitive returns because a fax arrives at one machine with a timestamped confirmation, while email gets forwarded, sits in inboxes indefinitely, and lands in the wrong hands more easily. This is general information, not tax advice.
| Document | Fax fit |
|---|---|
| W-2s and 1099s | Routine: these are the bulk of tax-season fax traffic |
| Signed engagement letters and organizer forms | Good: the confirmation proves when you engaged the firm |
| Prior-year returns and amendments | Good, but fax the return and keep the original filed copy yourself |
| IRS or CRA correspondence | Good: time-sensitive notices are exactly what the fax timestamp is for |
| Large brokerage statements | Ask first: long statements fax poorly; the firm may prefer a portal upload |
Three structural differences. First, email is trivially forwarded: one wrong click by an assistant sends your return to someone else, and email threads persist forever in archives you don't control. A fax goes to one number and stops there. Second, attachments rot: accountants' inboxes overflow in April, and "I emailed it" has no reliable proof of arrival. A fax confirmation has the date, time, and recipient number on one page. Third, tax firms process fax intake as a defined workflow: documents arrive, get stamped, and enter the return queue, while email attachments need someone to notice, download, and file them. During crunch weeks, the fax pile gets worked and the inbox gets buried.
Use the firm's dedicated tax-season fax line, not a general office number. Many CPAs publish a separate fax line for client documents during tax season, sometimes routing to a tax-only intake queue. Call the office and ask which line handles client source documents, then confirm the number digit by digit. Tax documents carry your Social Insurance or Social Security number, so a transposed digit is a real privacy event: treat the confirmation call as mandatory, not optional.
Print clean, dark copies. Tax forms with faint print, like old 1099s or faded W-2 copies, degrade in transmission and may come back as an illegible blur that the preparer can't work from. If a form is light, increase the contrast when you copy it. Keep the page count sane: a fifty-page brokerage statement faxes badly and costs the firm time to reassemble, so ask whether they'd rather have it through their client portal. Put your name and the tax year on every page and on the cover sheet, because tax offices process hundreds of client files in parallel.
If your accountant runs a secure client portal, use it for the bulk of your documents: it is the cleanest archive and the least error-prone channel. But keep fax in your pocket for two situations. One, deadline pressure: faxing a signed form on April 14 creates a timestamped record that portal uploads don't match. Two, when the portal misbehaves or the firm asks for it. Many accountants happily take documents by both channels; ask your preparer at the start of the engagement which they prefer for what, and follow that split all season.
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.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com