What log files? Apache web server log files? System history log files? Other log files? Normally, people who ask are referring to system history log files — the QHST* files in QSYS.
There are no commands to create those log files. They are created automatically.
Check out Bob Cozzi’s utilities. He has something that may do what you want. It writes some type of log file but I’m not sure exactly what type. It may only add records to QHST which can be handy for documentation purposes.
SNDPGMMSG ... TOPGMQ( *HSTLOG )
You can send messages to the history log with that command, if that’s all you want to do. Fill in other parms as needed, of course.