What are the Responsibilities of central banks
Responsibilities include providing banking services to commercial banks and the government and regulating financial markets and institutions. In this sense, a central bank is the "bankers' bank" - other banks can borrow from or lend money to the central bank.
Therefore, all banks in a country have an account in the central bank. When a commercial bank orders currency from the central bank, the corresponding amount is withdrawn from this account. This account is also used for transfers between commercial banks. Central banks also manage the country's foreign exchange and gold reserves.