We have found one software suitable in our database for this conversion.
Particular text-to-speech synthesizers allow users to create audio (like a .mp3 file) with a speech from a saved text file or document, but they are usually pretty expensive. And even that will, in most cases, require manual tweaking because otherwise, the audio would not be perfect.
However, you most likely won't find a simple docx to mp3 conversion that does the job with a single click.
Free text-to-speech converter Balabolka supports the import of Microsoft Word documents and direct conversion to audio files.
DOCX
Files with docx extension are documents written and saved using Microsoft Word word processor edition 2007 or later. DOCX format replaced the previously used DOC format, moving from binary files to Open XML schema-based documents. They are supported in almost every modern word-processing tools.
MP3
The mp3 file extension is traditionally used for one of the most common types of compressed audio files, MP3s, which you can playback using almost any media player.