Install tabcmd and run this script
cd C:\Program Files\Tableau\Tableau Server\Version\extras\Command Line Utility
tabcmd login "Server Name" -u username -p password
tabcmd export -t sitename "workbookname/Sheetname" --csv -f "Destinationfolder\Filename.csv" -u username-p password
This exports sheet to csv and stores in a specific location. Using other smtp tools like Blat, you could pick this file up and send it as an email. I've only did that once but you could research on internet on how to send an email using command scripts.
Thank you so much Maneesh
One doubt Manish, does this command helps in exporting the whole workbook or only a particular sheet in csv?
thank you maneesh