very newbie to Apache here

I installed Apache 2.4 on my Arch server where I installed newznab (a newsgroups indexer). I have noticed that all files newznab needs to create are created under my login user, and not apache default user (www-data). I read here that it's bad security practice to allow www-data to write files. I agree. But as an apache newbie, I would like to know where (in the httpd.conf I suppose ?) the user allowed to write files can be configured, because I want another account to be allowed to write files instead of my main account.