If the reason for canceling the account is your mistake, enter 10: then the PIB of your company in this field (eg: 10:112113489), if the reason for the cancellation is the request of a user who is a legal entity, enter 10: then the PIB of the user, if the reason for the cancellation is the request of a user who is natural person enter 20: then the user's ID card number (eg: 20: 110587556).