For example:

TABLE FILE CAR
HEADING
"SOME TEXT"
SUM SALES
BY COUNTRY
ON TABLE HOLD FORMAT WP
END

If you look at the output file, it has 2 leading spaces on each line. Is there any SET command which prevents that? (I have other solutions which require reading and re-writing the file)

Nope. It has been that way forever. There is also carriage control in a WP file. Have you considered another format, like SAVE? Examine your needs for wp and maybe that format can be replaced with another.

The 2 characters in WP format are historical "Print Control" from many years ago for Mainframe, they contain characters that cause a form feed , line feed, etc.

If you need Format WP, I would suggest re-reading the output file with another master file and use it to remove the leading chars.

Format WP historically used to be 132 chars wide, with later releases, this has increased. You will need to know what the width is, for you Master File.

You can use

? FILEDEF

after the hold to find out the record length.

Hope this helps