Do people and companies of USA and UK have a code or number of residence for tax and currence regulations?

Answer 1

Americans have a Social Security number that is used for tax and retirement purposes. It is also often used for credit reporting although it really should not be. We don't have any "number" that codes to our residency or has anything to do with currency regulations.

Brits have a National Insurance number that is used for the National Health Service, but again nothing tied to their residency or currency regulations.