Bitcoin isn't attached to a state or government, so itu doesn't have a central issuing authority or regulatory body, bassically, that means there's no organizational deciding when to make more bitcoins, digiring out how many to produce, kering track of where they are, so how does bitcoin work as a currency ?
bitcoin works as a currency because bitcoin has value and it applies the same value everywhere in the world despite its fluctuation that makes it accepted as exchange tool of transaction/payment. some other things have different value in different place that can't be exchange tool of transaction/payment.