Sending a Word file to someone who cannot open one: convert it first. Word to PDF, Word to JPG, Word to PNG. DOC and DOCX, 15 MB per file, deleted after.
To read it yourself instead, the Word viewer opens nine extensions and converts nothing.
Which output
PDF when the document has to stay a document — pages, layout, selectable text, one file. This is the default answer.
JPG or PNG when it has to go somewhere that only takes pictures: a chat message, a web page, a slide, a ticket attachment. PNG for anything with sharp text and flat colour, JPG when the page is mostly photographs.
What the converter takes, and what it does not
The converter accepts .doc and .docx. That is it.
The viewer accepts nine: .doc, .docx, .odt, .rtf, .docm, .dot, .dotx,
.dotm and .ott. The other seven open and read perfectly well but have no
conversion path. Open the file in Word or LibreOffice, save it as .docx, and convert
that.
Four things that change on the way out
Fonts. The converter uses the fonts on the server, not the ones on your laptop. A document built on a licensed corporate typeface reflows when a substitute stands in, and reflow moves page breaks. Embed the fonts first — File, Options, Save, Embed fonts in the file — and the layout holds.
Track changes and comments. They come through if the document is set to show markup. Review, then Accept All Changes, then delete the comments. Do this before converting anything that leaves the building.
Hidden text. Text formatted as hidden does not print and does not convert. If something is missing from the PDF and present in the document, check for it.
Links. Hyperlinks stay clickable in a PDF. In a JPG or PNG they are pixels of blue text.
Over 15 MB
It is images, essentially always. In Word: click a picture, Picture Format, Compress Pictures, tick "Delete cropped areas of pictures", pick 150 ppi. Save under a new name and convert that.
If the file is large because it is long rather than illustrated, split it and convert the halves.
The other direction
Received a PDF and need it editable? PDF to Word goes back the other way, up to 25 MB.