This is not related to CargoX (there is no such data on your CargoX account, but you can find your CargoX ID number here).
What your Egyptian importer probably wants from you is the passport number or the ID card number of the person that will use the system. Sometimes also their phone number will be acceptable.
Please check the official NAFEZA website for more information or contact NAFEZA by email at ACI.CAMPAIGN@MTS-EGY.COM.