(ADEXIT(ELAXMGUX)),ADATA,LIB,TEST&PARM
Suppose you want to generate side files for debug and are using COBOL source files in the project build. On the JCL Substitution page for COBOL settings, you would add PARM as the variable name and the desired option for the variable value.
The generated JCL for the project build will have a SET statement with PARM=option specified before the EXEC PROC statement, which will be substituted during the execution of the PROC.