int Led = 23;
int Relay = 2;
void setup()
{
  Serial.begin(9600);
  pinMode(23, OUTPUT);
  pinMode(2, OUTPUT);
}

  void loop() {
  if (Serial.available() > 0) {
    String command = Serial.readStringUntil('\n');
    command.trim();
    if (command == "on") {
      digitalWrite(Led, HIGH);
      digitalWrite(Relay, HIGH);
      Serial.println("Relay and LED are ON");
    } 
    else if (command == "off") 
    {
       digitalWrite(Led, LOW);
      digitalWrite(Relay, LOW);
      Serial.println("Relay and LED are OFF");
    } 
    else {
      Serial.println("Invalid command. Type 'on' or 'off'");
      }
  }
  }