To write code, you need a text editor (or an IDE, see next section). It does not matter which editor you use. There are thousands. Try a couple of them, and use the one you prefer. Here are a few.
Visual Studio Code (you know this one, a Microsoft product)
Sublime Text (you may know this one too)
Brackets (developped by Adobe)
Phoenix (an online version of Brackets)
Notepad++ (Windows only, very simple oldschool interface)
VIM (an old editor, extremely powerful, but difficult to use, only for nerds)
BBEdit (macOS only, my favourite everyday editor, not free but has a free version)
Light Table (a new one, I know nothing about it)
There are many others…