Board Thread:Support Requests - Designing Your Wiki/@comment-1883159-20191109001531/@comment-168424-20191109015938

Okay so there are two ways categories can be put on a page via wikitext and they do different things...
 * where this appears the page it is on will be added to the category called CATEGORYNAME; the entry in the category list will sort based on the SORTKEY (using just a space character: like, will sort it above everything else rather than putting it under a number or letter); nothing will be seen on the page itself where this wikitext is included
 * this just creates a link to the category page at Category:CATEGORYNAME
 * this just creates a link to the category page at Category:CATEGORYNAME
 * this just creates a link to the category page at Category:CATEGORYNAME

So, if you want to include a page where the template is used in a category, use the first type and if you just want a link, use the second type. If you want to do both, you need to use both types, i.e.  and only a link   (whatever is in the variable) will actually be visible.