I am trying to read data from Excel sheet which consists of Request and Response, signals with values in CAPL.
How to read from Excel sheet through CAPL scripting?
Only if you save your excel in a csv format. You cannot open xlsx through CAPL.
When you have a csv file, you can read it with the CAPLs regular file operation functions :
openFileRead();
About their usage you will find plenty documentation in Help.