Do you mean if you can save files with parameters in JSON format?
Yes, you can. However, I don’t know if that particular ESP8266 example works for the ESP32. I haven’t tried it.
One of our readers shared his code to read SSID and password from a file. You may find it useful and you can find it here: https://rntlab.com/question/read-spiffs-file-line-by-line/