Depending on the country, the unique company identifier is neither the SIRET, nor the VAT number, nor the CIK code.
Simple CRM allows you to rename the field "Num CIK" according to your needs.
go to the CRM Admin (top menu -> CRM Admin)
click on the "Settings" tab
in the "National Company ID Label" field, enter the name of the company ID
The field named "Num CIK (US)" is renamed according to your input (in our example: "Num BIF").