When I select the Destination Type as "Export to data files", I am able to download the output file using batch id from the abbyy cloud.
Suppose if I select "Custom export(script)" in Destination Type, how I can mention the same export path in the script?
You cannot obtain the defined Export path value in the export script. The File will be saved in the DB of the Flexi Capture Cloud and can only be retrieved via the API. However the export script and its IDocument object has many options.
https://help.abbyy.com/en-us/flexicapture/12/developer/idocument/