String to csv file

Hello, I've a problem.

I have clear string "a,b,c,d" and I need it convert to csv file like 'a' in one column, 'b' in second column etc.

I tried some things but maybe I don't know how to correctly set up nodes.

Anyone help?

Thanks ..

not quite sure I understand ? 99% of apps will read "a,b,c,d" as a csv line.
just send that to a file out node