Board Thread:Support Requests - Designing Your Wiki/@comment-27756776-20180413155043/@comment-9605025-20180413171336

You can use Special:WikiFeatures to disallow anonymous editing. Users will still be able to view content without logging in but in order to comment and contribute they will need to login.

Another option, if you are an admin, is to protect individual pages. This needs to be done one a page-by-page basis and, as a general rule, most pages should be left unprotected. Doing otherwise goes against the general concept of having a wiki in the first place. If you choose to use this method, you can independently choose restrictions on editing the page and moving the page. There are 3 levels of protection as described in the article I linked to.