Help:Gadget-HotCat

HotCat is a extension where you can easily add categories onto a page without editing the article.

Usage
If you feel like the page needs another category, click on the (+), a bar will show up and you can type whatever category you want it in. If the category exists, it will autocorrect it. If the category doesnt exist, then you can still add it by typing it. But make sure to make the category page and make a description.