Can I send a Word file to someone who does not have Word?

Usually yes — Google Docs, LibreOffice and Pages all open .docx. But each renders it slightly differently, so pagination and font substitution can change. If the layout matters, send a PDF.

Is a PDF smaller than the equivalent Word file?

For text documents they are broadly similar. For image-heavy documents the PDF is often smaller, because export re-compresses pictures that Word may have stored at full resolution.

PDF or Word: choosing the right format for a document

Use Word while a document is still being written, and PDF once it is finished — the formats are built around opposite assumptions about change.

The two formats are built on opposite assumptions, and almost every awkward document exchange comes from using one where the other belongs.

The core difference

A Word document describes content that flows. It stores a stream of paragraphs, styles, tables and section rules, then works out at open time where the page breaks fall. Change the font, the paper size, or the printer, and the layout recalculates. That flexibility is exactly what you want while text is being written and revised.

A PDF describes marks at coordinates on a fixed page. Nothing recalculates. That rigidity is exactly what you want once the text is final and the layout has to survive the trip to someone else's machine.

Neither is better. They solve different halves of a document's life.

Send Word when

The recipient needs to edit, comment inline, or track changes.
The document is a template others will fill in.
It will be merged into a larger document later.
You are collaborating with people who use the same office suite.

Send PDF when

The document is finished and should not be casually altered.
Layout matters: an invoice, a contract, a certificate, a CV, a design proof.
You do not know what software the recipient has.
It needs to be printed exactly as designed.
You are submitting it to a portal, a client or an authority — most explicitly require PDF.

Converting the finished version with Word to PDF is the last step of most document workflows, not an afterthought.

The trap: sending Word when layout matters

A .docx does not carry its fonts. If your CV uses a typeface the recipient does not have installed, their reader substitutes something else, line lengths change, and a carefully balanced two-page layout becomes an awkward two-and-a-bit. Field codes such as page counts and cross-references recalculate on the recipient's machine. Comments and tracked changes travel with the file unless you accept and remove them — a genuinely common source of embarrassment.

The other trap: sending PDF when editing is expected

If a colleague needs to revise your text, sending only the PDF forces someone into a conversion round-trip that will lose structure. PDF to Word reconstructs text and basic formatting from positioned glyph runs, but it is rebuilding from geometry, not recovering the source. Styles, section breaks, automatic numbering and table semantics do not come back intact. See why formatting changes during PDF to Word conversion for the mechanics.

The professional answer is to keep the editable source and treat the PDF as an output, not as the master copy.

Where they overlap

Both formats can carry fillable forms, and both can be signed. A PDF form is generally the better choice for anything distributed widely, because the field layout cannot be accidentally dragged out of place while someone fills it in. For a visible signature on a finished document, stamping it onto the PDF with Sign PDF is simpler than manipulating a Word file — though as our signing guide explains, a drawn signature is not the same thing as a certificate-based digital signature.

A rule that works

Keep the editable master in a word processor. Export a PDF whenever the document leaves your hands. If you find yourself converting a PDF back to Word, that is usually a signal that the source file was lost or never shared — fix the process rather than the file.