NTPClient

#include <NTPClient.h>
// change next line to use with another board/shield
#include <ESP8266WiFi.h>
//#include <WiFi.h> // for WiFi shield
//#include <WiFi101.h> // for WiFi 101 shield or MKR1000
#include <WiFiUdp.h>
const char *ssid = "<SSID>";
const char *password = "<PASSWORD>";
WiFiUDP ntpUDP;
// By default 'pool.ntp.org' is used with 60 seconds update interval and
// no offset
NTPClient timeClient(ntpUDP);
// You can specify the time server pool and the offset, (in seconds)
// additionally you can specify the update interval (in milliseconds).
// NTPClient timeClient(ntpUDP, "europe.pool.ntp.org", 3600, 60000);
void setup(){
 Serial.begin(115200);
 WiFi.begin(ssid, password);
 while ( WiFi.status() != WL_CONNECTED ) {
 delay ( 500 );
 Serial.print ( "." );
 }
 timeClient.begin();
}
void loop() {
 timeClient.update();
 Serial.println(timeClient.getFormattedTime());
 delay(1000);
}

Function documentation