Code for interfacing arduino with rfid(em-18) reader module

Answer 1

This isn’t the best place for arduino
Try google or YouTube

Answer 2

these are the first 3 results of a google search for: "em-18 rfid reader arduino".
in the links you'll find wiring, schematics and code.
last one is a video.

http://www.instructables.com/id/EM-18-RFID-Reader-Module-Interfaced-With-Arduino-U/

https://electrosome.com/em-18-rfid-reader-arduino-uno/

https://m.youtube.com/watch?v=4mXsaFyxG7Y