Board Thread:Support Requests - Community Management/@comment-7194762-20200220125549/@comment-9605025-20200221031345

I can't recall Miraheze's policy but they at least allow private editing. However, from what I can tell, Miraheze is run by a group of "volunteers" so I don't know how much support you will get. You can use ShoutWiki which is "professionally run" and offer completely private wikis, I think at no cost. There is a paid tier system but I believe that is related to support and features, not the type of wiki you can create.