To write your email into the Citizen Digital Certificate will enable secure email with digital signature in Microsoft Outlook or Outlook Express. Please reference explanations in Interior Ministry Certification Authority website for its installation. If you do not write your email, you will not be able to use above feature. However, it will not affect your use of certificate either.

You can go to any household registration office (not necessarily the one you have had your application) that accepts Citizen Digital Certificate IC card application. Tell the counter staff that you want to change your email address. No fee is needed for changing Email Address.