To maintain security this OTP is valid only for a few minutes and if transaction does not go through in stipulated time, there will be a timeout and user will have to generate a new OTP to initiate the transfer. Sophisticated, high-volume exchanges are preferred, if not required. This is a one-time process. Copy the address in its entirety and go to your wallet of choice. If you plan on buying a large amount, does the exchange support this much in exchange? Bank transfer buys can take days to clear. We may receive compensation when you use Coinbase.