I might like to help, but your post has me confused. Perhaps you could clarify what you're looking for, what you've already done, and where specifically you need help.
You said:
I need to know how can I create a panel using REXX.
You CREATE a panel definition using the ISPF panel language. You can
DISPLAY an ISPF panel using the standard ISPF Dialog command DISPLAY, in REXX or any other language. If you just want to CREATE a panel, I'd suggest that you use on of the pre-defined panel models (the Data Entry model would be a good one to use) in your own panel library and make your changes as needed.
You said:
In this panel I need to have two input variables, one a search string another the path name in which the search string is to searched ( similar to 3.14 option ) and the ouptput should be saved in a dataset.
Why are you re-designing an existing ISPF function? Anyway, if the ISPF 3.14 option is close to what you need, then why not just use that panel's design as a template for yours.