PDF or Word: which should you send?

The short version

Send a PDF when: the document is finished; it will be printed; the layout matters; it needs a signature; it is going to a client, a court, a government form or an archive; or you simply do not want it altered. Every reader on every device shows the same thing, and Word to PDF produces one in a step.

Send the editable file when: someone is meant to revise it; it is a template; you are collaborating; or it is going to a translator or a typesetter who needs the text as text.

Send both when the answer is genuinely “read this, and here is the source if you need it”. It costs one extra attachment and prevents the entire round trip described below.

What actually differs

A word processor file stores a stream of content with rules about how to lay it out: this is a heading, this is a list, this paragraph has these margins. The layout is computed when you open it, which is why the same file can look different on a machine with different fonts, a different page size or a different version of the software.

A PDF stores the result of that computation. Positions are absolute and fonts travel with the file.

This is the whole trade, and it is not a matter of one format being better. Fixed layout means guaranteed appearance and painful editing. Reflowable content means easy editing and no guarantee at all about what the other person sees. Choose by which of those two properties you need for this particular document.

The round trip, and why it hurts

Going Word → PDF is clean. Everything the PDF needs is known: the layout has been computed, so it is simply recorded.

Going PDF → Word is a reconstruction. The converter sees glyphs at coordinates and has to infer what they meant: which marks formed a word, which words formed a paragraph, whether this run of aligned text is a table or a coincidence, whether that gap is a margin or an empty cell. Good converters infer well. None of them know, because the information was discarded when the PDF was made.

So the practical rules are:

• Keep the original. One kept source file saves every future round trip.
• Do not use PDF as a working format. Editing a PDF, exporting to Word, editing, and re-exporting loses a little each time.
• If you must convert back, expect to fix the layout, and read what a converter can and cannot recover first. PDF to Word will get you most of the way.
• If the PDF is a scan, conversion returns pictures until you run OCR. There is no text in the file to convert.

Practical points people hit

“They asked for a PDF but want changes.” Ask what they actually need. If it is comments, most readers can annotate a PDF without touching the content, which is usually what “edit” means.

“The PDF is enormous.” Word files compress images aggressively; exporting can produce something far larger. Compress PDF fixes it, and PDFs too large to email covers the limits you are up against.

“It needs signing.” Send a PDF. Signatures on editable documents are close to meaningless, since the document can change afterwards. How to sign a PDF explains the difference between an image of a signature and a cryptographic one.

“It has to be filled in.” A PDF form is designed for exactly this and keeps the layout fixed while the fields stay editable. See how PDF forms work, or fill one in.

“It is going into a system.” Check what the system wants before deciding. Many accept only PDF; some require PDF/A; a few need the editable original.