Optional for most industries, but mandatory for some industries which requires you to be qualified to provide services. Depends on your profession, this can be either a council membership card or an accredited certificate for your profession. Adding this will speed up your review process.
We need this for banking and legal purposes since we will be depositing your earnings into your bank account frequently. We comply with the EU AML/TF regulations. We also take your privacy very seriously and protect your personal data. As an Expert Republic Expert/Customer you can always exercise the "Right to be forgotten" clause of GDPR.