Why send a PDF rather than the document
Three reasons, and they are worth separating because they suggest different amounts of care. A PDF looks the same everywhere, since the page layout is fixed rather than reflowed by whatever software opens it. It embeds its fonts, so a house typeface does not silently become Calibri on the recipient's machine. And it signals that the text is finished — a document that arrives editable invites edits.
None of that applies while you are still drafting. Send the working file to collaborators and the PDF to readers.
A .docx is a ZIP full of XML
This is why a browser can read one at all. Rename a Word file to .zip, open it, and inside is a folder structure: the text lives in word/document.xml, with styles, images and settings in files alongside it. Unpacking that in the browser and reading the XML is what happens when you select a document — nothing leaves your machine.
The older .doc extension is a different thing entirely: a binary compound format from the 1990s with none of that structure. It cannot be read the same way, so it is refused rather than half-parsed into nonsense. Open it in a word processor and save it as .docx first.
What comes across
The text and its structure, which for most documents is the substance:
- Paragraphs, in order, with blank lines preserved.
- Headings, where you used Word's Heading and Title styles rather than manually enlarging text.
- Bold, italic, underline and strikethrough.
- Lists, both bulleted and numbered.
- Tables, as plain bordered grids of cells.
Two caveats inside that list. Numbered lists arrive as bullets, because the numbering scheme lives in a separate part of the package that is not read — if the numbers carry meaning, as they do in a set of clauses or steps, type them into the text before converting. And tables lose merged cells, column widths and heading-row styling; a complex table will be legible but not identical.
What does not come across
Everything that depends on Word's layout engine rather than on the text. Images and logos, text boxes, shapes, charts, multi-column layouts, floated objects, page headers and footers, footnotes and endnotes, and any font, size or colour you applied.
Exact pagination goes with it. Page breaks are decided by the browser at print time, so a document that ran to six pages in Word may run to five or seven, and a heading that sat neatly at the top of a page may not. For a memo or a report body that is a non-issue. For anything where the page count is referenced elsewhere, it matters.
Two things to check in the source first
Tracked changes. Insertions are read as ordinary text and deletions are dropped, so the output looks as though every change was accepted — whether or not you had decided to accept it. Resolve the markup in Word before converting, or you may publish a revision you were still arguing about.
An automatic table of contents. Word stores the last-generated version as plain text, listing page numbers from the original pagination. Those numbers come through and will not match the new document. Either delete the contents page before converting or accept that it is decorative.
Comments are not carried over, which is usually what you want, but do not treat that as redaction — check the document rather than assuming.
The print dialogue makes the file
The converted text opens in a new tab and the browser's print dialogue appears; choosing Save as PDF as the destination writes the PDF. If no tab opens, a pop-up blocker stopped it — allow pop-ups and try again.
Three settings repay attention. Turn off the browser's headers and footers, or every page carries a URL and a timestamp. Check the paper size, which follows your system locale and is A4 in most of the world and US Letter in North America. And glance at the margins, since the default is generous and a document that runs to five pages often fits four at a narrower setting.
When to use the word processor instead
Being honest about this is more useful than pretending otherwise. If you have Word, LibreOffice or Google Docs open with the document in front of you, their own PDF export is the better route: it reproduces the layout exactly, carries the images, keeps the footnotes and the headers, and preserves your pagination. That is what it is built to do.
What [msm_tool slug="word-to-pdf"] is for is everything else. A document that arrived by email on a machine without Word installed. A phone. A borrowed laptop. A file you need to read and forward now, where the substance is the text and the exact spacing of the third page is nobody's concern.
Whichever route you take, open the finished PDF before sending it. Check the first page, the last page, and any table in between — those are where a conversion shows its seams, and it takes fifteen seconds.