A CSV file contains data.
A macro is like a sub program for generating SAS code.
Are you asking how to output the code that defines your macro to a comma delimited file? What would the commas delimit?
A macro variable contains a text string.
Are you asking how to output the value of a macro variable to a CSV file? What part of the CSV should the value be written into?
You use the macro processor to help you generate code.
Why don't you start by explaining what code you need to generate? What parts of it need to change that could benefit from the use of either a macro variable or executing a macro?