@hossein890 Did you name your working module docx.py perhaps? That will cause import docx to load your current project code module instead of the library. The Python module loader gives preference to ...

Python module for exporting a csv (selectively) to a docx, controlled by a json config file - RandySage/csv2docx ...

This post explains what a Python module is and how to use it to drastically extend the capabiltiies of your code. Plus: how to make your own!