You asked a similar question before.
The uvm_sequence response_handler() work like the the uvm_subscriber write() method. (It is too bad the UVM committee did not use the same name so would would be exactly like the write() method). Both get called with an input argument that has a handle to a transaction constructed in the driver or monitor. The sequence provides the “implementation” of the response_handler() method and reads the information it needs out of the transaction that was passed to it.