Signing a document before you fax it
Handwritten, drawn or electronic: how to sign, and what the receiving fax machine actually prints.
To fax a signed document, sign the paper in dark ink and scan it in black and white, or add a drawn signature to the PDF. Whatever the method, the recipient gets a picture of the signature, never an electronic signature they can verify. Where an original paper copy is required, a fax does not replace it.
Key points
A fax carries a black-and-white image: the signature arrives as a drawing, with no certificate or timestamp.
A certificate-based digital signature loses its verification value as soon as it is printed or faxed.
Initial every page and number them "1 of 4, 2 of 4…" so the recipient sees at once if a sheet is missing.
At 204 × 196 dpi a very fine stroke breaks up: sign with a medium tip and black ink.
Three ways to sign, and what the recipient receives
The choice depends on what the recipient accepts and on your equipment. The middle column shows what comes out of their fax machine.
| Method | How to do it | What arrives by fax | Suited to |
|---|---|---|---|
| Handwritten, then scanned | Print, sign in ink, scan to a black-and-white PDF. | A copy of the original signature, usually the sharpest result. | Government forms, cancellation letters, simple authorizations. |
| Drawn in the PDF | Draw the signature with a finger or stylus in a PDF app, or insert an image. | An image of a signature that looks the same as the one above. | Everyday sending when you have no printer or scanner. |
| Electronic or digital | Sign with a certificate or an e-signature platform. | Only the visual appearance; the certificate and integrity check stay in the original file. | Sending the file through an electronic channel, not by fax. |
Handwritten signature: getting the scan right
Print the page, sign it, then scan it in black-and-white mode (sometimes called "text" or "document") rather than colour or greyscale. That mode produces pure black or white pixels, just as the fax machine will, so the screen shows you what the recipient will get.
A flatbed scanner gives the best result. With a smartphone, lay the sheet on a dark, plain surface, light it from the front with no shadow, and use the phone's document-scanning feature, which straightens the page and boosts contrast. Then zoom in on the signature in the PDF: if the line looks dotted, raise the contrast or sign again with a firmer stroke.
A signature drawn in a PDF
Most PDF readers and mobile apps include a "Fill & Sign" tool: you draw your signature once, the app saves it, and you drop it onto the document. It is handy for quick sending from a phone, with no printer.
Two precautions. Draw the signature large in the input area, then shrink it on the page: a signature drawn small to begin with often ends up as a few straight segments. Then flatten or export the document as a standard PDF before sending, so the signature is part of the page and not an annotation that some software might not display.
Electronic signatures: why a fax cannot carry one
In Canada, electronic signatures are mainly governed by provincial electronic commerce or electronic transactions statutes, such as Ontario's Electronic Commerce Act, 2000 or British Columbia's Electronic Transactions Act, and federally by PIPEDA, which also defines a secure electronic signature for certain federal purposes. Broadly, these laws accept that a signature is not invalid just because it is electronic, but each one lists exceptions, such as wills or certain land documents. Check the rules that apply to your document and province.
A certificate-based digital signature relies on cryptography stored in the file: a fingerprint of the document, a certificate, sometimes a timestamp. A fax sends only a dithered image of the page. A digitally signed PDF that is faxed therefore arrives as a plain copy: the recipient may see a "signed by…" box but cannot verify anything.
If the recipient requires a verifiable electronic signature, send the signed file through the channel they specify (portal, secure upload, email). Fax remains suited to documents for which a signed copy is enough.
When the original paper is still required
Some documents still call for an original: notarized documents, certain contracts, and items an agency asks for "in original" on its form. In those cases a fax can serve as advance notice, or meet a deadline if the recipient accepts it, but the original must follow by mail or be dropped off. The exact list depends on the organization: read its instructions or ask.
For multi-page documents, initial every sheet in the same place, bottom right for instance, and number the pages as "page 2 of 5". Initials show the signer saw each page; numbering lets the recipient check the transmission is complete. Keep the signed original with the transmission report or confirmation.
Keeping a signature readable at 204 × 196 dpi
- In fine mode a fax has about 8 dots per millimetre: a very thin pen line can fall between two dots and vanish.
- Sign in black ink with a medium tip or felt pen; pale blue and pencil do not survive the black-and-white threshold well.
- Keep the signature area clear: a stamp, a grey background or a line of text running through it muddles the stroke.
- Give the signature a normal size, at least the height of two lines of text; a tiny signature turns into a blot.
- Before sending, view the PDF at 100% in black and white: what you see is close to what the recipient will print.
A cover page states who is sending, to whom and how many pages follow, which helps the recipient match the signed document to the right file. Create a free cover page
Signing and faxing: your questions answered
- Does a signature drawn on a phone count as much as a scanned handwritten one?
- Once faxed, both arrive as images and nothing technically sets them apart. The recipient, or the rule that applies to their file, decides whether a signed copy is enough.
- Can I fax a PDF I signed with a digital certificate?
- Yes, but the digital signature does not survive the fax: only its appearance is transmitted. If the recipient must be able to verify it, send them the PDF file itself through an electronic channel.
- Does the cover page need a signature?
- Usually not: the cover page describes the transmission. It is the pages of the document itself that need signing and initialling.
Fax in practice
In this section
Where to go next
Hand-picked pages to help you prepare, send or prove your fax.
- A handful of fields, one PDF to download, placed at the front of your fax.
- Articles 1358, 1366 and 1379 of the French Civil Code, read from a fax user's point of view.
- Your phone can send a fax. It cannot be the machine that takes one.
Recent guides
Blog articles on the same subject.