If you want to delete all files given type (*pdf) older than 10 days from specific folder you can use this command directly from IBM i command line.
/QOpenSys/pkgs/bin/find - is used because IBM i find command doesn't allow -delete option.
QSH CMD('/QOpenSys/pkgs/bin/find /directory_where_files_are/ -mtime +10 -type f -name ''*.pdf'' -delete')