Tried Notepad++? It handles text documents in bulk just fine, is lightweight, easy to use and free, and also has code support (don't expect code suggestions - it is not meant to code in the developer's stead and that is a good thing).
It has a built-in find-all-replace-all feature with multiple modes, search and compare markers, code formatting for tons of languages and even comes with the JSON parser and formatter plugin now iirc. If it doesn't, you can always grab plugins you want/need later, it's really easy.
I'm only suggesting this because you're on a Windows environment, and of course there are many alternatives. You don't need an IDE (integrated development environment) if all you're going to do is code, edit and type in pure text, that would be wasting hundreds of megabytes and bloating your operating system, as well as making you grow terrible habits with the fancy hand-holding and code assist. Hell, Eclipse, Visual Studio and shit like that also have "quick problem solving" features. You can see projects going souther than south if aspiring developers start to overly rely on it and let it decide everything for them for years, essentially causing the project to become some kind of disassembled garbage dump.
tl;dr: Use a lightweight text+code editor you like with fancy features but don't let the bloat invade your environment.
Also, "text document" is pretty broad so don't let that intimidate you. JSON is a data interchange format made for this.
Edit: Grammar.