Auto Update data from one column in Excel file A to another column in Excel file B

HI,

I have 2 excel files for example called A, and B.

In File A, I have names of employees like this and new employees will be entered here continously.

      A                        B      
1    Employee code           Name
2    001                    Peter
3    002                    John
4    003                    Alex
5    004                    Lucis

I would like to update Employee code column in File A to a column (lets say column B) in File B automatically when there is new employees entered in File A.

Please show me how to achieve this with either Excel built-in functions or Macro.

Best Regards,
Ryan