One of the most popular functionalities of javadocx is transforming between different document formats. You can convert HTML to DOCX, DOCX to PDF, DOC to DOCX, ODT to DOCX, among many more document formats.
Conversion from HTML and CSS to DOCX allows to generate MS Word contents with HTML tags and CSS styles.
The page HTML and CSS of this practical guide offers more information about this functionality.
Converting DOCX to PDF requires using transformDocument:
You can transform documents created from scratch with javadocx, or generate them with any other application, like MS Word, LibreOffice or another external library.
Many other document formats are compatible: DOC, ODT, RTF… Thus, it is possible to convert DOC documents to DOCX to use the set of methods of the javadocx API, and then transform them again from DOC to PDF of any other document type:
The introduction to the conversion plugin lists all the compatible formats.