I came back with a sugestion I made in another thread of this forum.
It may be useful to have a first (required!) field - Customer Type (person or company).
Then, if Person - automatic display required fields Name, Personal Identification Number etc.
If Company - automatic display required fields Company Name, Company Identification Number, VAT ID etc.
I guess I can modify myself the files for this purpose, but I think it would be a real gain for all JShop users to have it included by default in the code.