Which direction does it convert?

Both: EPUB → printable PDF, and PDF / text / Markdown → a valid EPUB 3 that works in Apple Books, Kobo and Calibre.

Do DRM-protected books work?

No — DRM can't and won't be bypassed. This is for open, DRM-free books.

Chapters, headings and text. Publisher CSS styling and embedded images aren't reproduced — it's a text-focused conversion.

Convert a DRM-free EPUB book to a printable PDF entirely in your browser — chapters, headings and text preserved.