DOCX for collaborative edits
A word-processing document is usually the practical choice when someone else must suggest corrections, track changes or rearrange paragraphs. Share DOCX for work with an editor, but check fonts, tables and page breaks in the app used by your collaborator.
PDF for fixed pages
PDF is useful when the recipient needs to see the same layout, such as a worksheet, formatted report or print-ready preview. It keeps placement and page numbers more stable than reflowable formats. The trade-off is that reading small print on a phone can require zooming.
EPUB for reflowable books
EPUB suits many novels and text-first books. Readers can change text size and the display adapts. Good EPUB export needs a proper table of contents and semantic headings, not simply a renamed DOCX or ZIP file. Complex image layouts may need extra work.
Keep the editable source
Do not rely on a final PDF or EPUB as your only manuscript. Keep a working document and a dated backup. Export a short sample first and open it in another app. Check chapter navigation, italics, footnotes and any images; fixes are easier before you send a complete book to readers.
If you will publish through a particular store, read its current upload rules before choosing an export format. Different stores and printing services accept different files.
Once you export your draft, use Readream Basic to read the DOCX or EPUB as a reader would. Look for awkward paragraph breaks and missing images before sharing it.