Ad-ID is the standard identifier for advertisements in the United States, however, Ad-ID codes can be used internationally if a company wants to use Ad-ID to manage their assets globally. There may be other standards or requirements in other countries so we recommend that you confirm for each country to make sure you don’t need to use an alternate identifier.
The Ad-ID system also has a field for an alternate identifier if you want to create an Ad-ID code and associate it to another identifier that may be required in other countries.