Do you want someone to give you his or her Hong Kong ID Card number?
YES
NO

If you are asking the individual to furnish an ID Card number or other personal identifier or show the ID Card, but you will not record it, please see the note here

If the individual concerned is no longer living, please see the note here.

If you are collecting ID Card numbers or other Personal Identifiers or copies of ID Cards for purely personal or family use, please see the note here.

 

Part II in the Code is the general reference for this.