$USDC USDC operates on a Mint & Burn mechanism, existing as an IOU (I owe you) that can be used to exchange for an equivalent amount of dollars outside the blockchain ecosystem.
Users mint new USDC by sending fiat currency to financial institutions regulated and licensed by Centre. If users want to redeem USDC, they can send USDC to an address controlled by Centre members, who will burn the USDC and transfer the equivalent fiat amount to the user's bank account. Centre currently has two members: Coinbase and Circle.