C:\Users\Guest_Melik\Documents\Arduino\keypadservo\keypadservo.ino:5:18: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
char* password = "123";
^~~~~
That is a warning, not an error. It is warning you that it may cause problems. If you are never going to change the value of password in the sketch then use