If you want to make a forum, you have to get hosting, and processing power to actually run your forum and blog as well. However, with a blog you can get away with not paying for hosting, and you can instead write HTML pages yourself. I would strongly advise you to not use WIX, because it's a closed ecosystem. You get in, you create your blog or forum, but you cannot export your data, or move away from them easily without completely rewriting your blog and recreating your forum. You own your blog and you should have control over it. You can however use Worpress.org as your blog, but you need a server or somewhere you can store Wordpress, like hostinger. For the forums, it's very hard to create one from scratch, but there are open sourced forum interfaces and everything, allowing you to set it up easily. Then you can make your app.
