Write data to shared network folder.

Hi - I'm trying to write my Arduino sensor data to a shared network folder on my PC. I want to use the Ethernet cable to do this and was wondering if there is any way of directly pushing the data into a CSV file in the folder. I found some stuff online but they all include setting up GET requests in HTML.

It's probably easier to write a Python or PHP script that receives the data and writes it to the file. (Arduino as client, Python/PHP on the server side)
Or you could reverse the roles, and have the Arduino act as a server, serving the CSV file to any client that requests it (a web browser, wget, Python ...)
Here's an example that demonstrates the second option. I wrote it for the ESP8266, but the principle should be the same.

Or you could do it the hard way, and teach the Arduino to talk SMB, but I'm not sure how that's going to work out ...
Using the Arduino as an FTP client could work.