Problem:
While trying to compile your ESP32 application, you see this compiler error:
fatal error: ESP8266WiFi.h: No such file or directory
Solution:
ESP8266WiFi.h is the Wifi header for the ESP8266. For the ESP32, it’s named WiFi.h. In order to fix the issue, replae
#include <ESP8266WiFi.h>
by
#include <WiFi.h>