
There are two ebook formats:
• PDF format, widely distributed for printing, but inappropriate for ebooks, smartphones
• EPUB format, free ebook format for electronic reading
To create a PDF file, just export your creation to PDF. Do not use printing to create your PDF, but export the fonts. Indeed, printing creates your book in pictures.
Free tools exist to create an EPUB file.
LIBRE OFFICE, CALIBRE or SIGIL make it possible to convert text files into EPUB, keeping the written information.
There are also plugins for OPEN OFFICE and FREE OFFICE, so writer2epub.