How do I buy and sell digital currency?

Related questions

1. What is a QR code for digital currency?
2. Who is the creator of digital currency?
3. Is Canada going digital currency?｜Canada's central bank, the Bank of Canada, has stated that. That said, they are researching digital currency systems and business models while working on building the capability to issue a digital version of the Canadian dollar (a CBDC ).they do not have plans to issue a digital currency any time soon