How do I add fields to incoming data?

Hi, I'm trying to load a CSV file using the universal forwarder, and there are no headers in the CSV file. How can I give column names to those values in the file? Can I do that at props.conf? I don't want to use the extract field option... eg : file.csv as below values 1,2,3,4,5 6,7,8,9,10 11,12,13,14,15