Within the European Economic Area (EEA), countries maintain national databases of company information. When signing up or updating your profile, you can provide a registration number. What number should I use for this?
The European Union maintains a list of registries in the various member states of the European Economic Area. It can be found here. Preferably, use the identification number associated with the register included in this list. If there is no (national) registry in your country, leave the field blank.