<snip from wiki> a.. Another handy option to take care of this is to pass spamd the -H option with /etc/mail/spamassassin as the argument. This sets all helper apps' (dccproc/pyzor/razor) homedirs to /etc/mail/spamassassin.
Where do I put the -H option, where is the config file or what is it called?
It's a command-line parameter, not a config file. It only matters if you use razor, pyzor, dcc, etc. It does not affect the main of spamassassin.
If you want to change what home-dir these external aps use, set this parameter.
If you don't understand, or don't want this behavior, ignore this entirely.
<snip from wiki> a.. Make sure anywhere you're calling spamassassin in a script/procmail recipe/.qmail file to always use the -C /etc/mail/spamassassin configuration option so it will pick up the razor_config option, and in turn the razorhome setting in razor-agent.conf
Again, how and where? Is THIS refering to spamc, and if so, should it actually read as -c not -C?
No.. they explicitly say spamassassin. spamassassin is not spamc. If you're using spamc, ignore this advice, or move the parameter to your call to spamd.
If you call spamassassin, not spamc, you might want to heed this advice.
However, I suspect the entire entry is an error. Where'd you find it in the wiki?