hi
I am new in houdini and I would like to ask you what is the difference between the VEX and Python in houdini and what is the most important for the Fx

They are two different languages.

Python is the standard implementation as you may already know it. Houdini provides a module named “hou” that you can import and access the API from. Many of the interface tool buttons are written in Python. You can right-click on them and view the code that runs when you click them.

VEX is a language specific to Houdini and has a more C-like syntax. It is used more in-line when modeling or simulating to change or update values.

VEX is multi-threaded in most cases while Python is still single core.

VEX is the most important to learn first.