To read data from the external flash do we send dummy data, In QSPI protocol

In SPI you send dummy data to clock the interface, the QSPI isn't typically doing that, you're clocking it and getting 4-bits back in every cycle, the bus isn't changing direction.

If you have doubts, look at the data sheet for the QSPI memory you are using, and the commands you are sending. If you need more validation, use a logic analyzer and observe directly.