Your question is too vague. "Remove leading zeros" can mean many things.
Please show an example of the records in your input file (relevant fields only) and what you expect for output. Explain the "rules" for getting from input to output. Give the starting position, length and format of each relevant field. Give the RECFM and LRECL of the input file.
(In the future, if you want a faster answer, I'd suggest spending more than 5 seconds composing the question. Include enough information with your first post so people know what you're trying to do. I'm happy to help, but I can't read your mind.)