My writing app won't export EPUB or PDF

Route it through a format the app does export

Almost every writing app can hand you a Word file, Markdown, or plain text, even when EPUB and PDF are missing or locked behind a plan. That file is the bridge. Before you export, make sure each chapter title is a real heading (a Heading 1 style, or a single # in Markdown) and not just bold text, because every tool below finds chapters that way.

From there, pick the route that fits what you need:

• A PDF to read or send. Open the DOCX in a word processor and save or export it to PDF. Word, LibreOffice Writer, and Google Docs all do this without add-ons.
• An EPUB, with a few clicks. Calibre is free and runs on Windows, Mac, and Linux. Add the DOCX to its library, choose Convert books, and set the output to EPUB. By default its Structure detection treats a level-one or level-two heading as a chapter when its text contains Chapter, Book, Section, or Part; widen that rule there if your titles are just names.
• An EPUB from the command line. Pandoc converts DOCX or Markdown in one line, for example pandoc book.docx -o book.epub --metadata title="My Novel". It splits the book into a new file at each top-level heading. Pandoc can also make a PDF, but that needs a LaTeX installation or another PDF engine alongside it.
• A retail-ready ebook or print file. Import the DOCX into a dedicated formatter or the retailer's own tool. Amazon's Kindle Create, for one, is free and reads Word files.

Before you upload

Open the EPUB in Kindle Previewer or a second reader app and click through the table of contents. Italics, scene breaks, and any special characters are the things a conversion most often trips on. If a store will validate the file, running EPUBCheck yourself first saves a rejected upload.

In Tabularia

EPUB and PDF are both on the export list on every plan, alongside DOCX and the rest. No bridge format is needed. The Export dialog's Scope can also narrow an export to one Act, one chapter, or a draft.

Know what each file is for. The EPUB is a preview for e-readers. The PDF is a paperback interior at your chosen trim size, with every typeface embedded and optional bleed; before it downloads, the dialog lists what KDP would refuse, such as an inside margin too narrow for the page count. For a retail ebook, finish in a formatter, or take the DOCX there.

Moving a book in from a writing app that lacks these exports is covered in Coming from another writing app.