For Windows, I use Notepad++, and when I'm lazy, Notepad.
For Mac, I just don't code on it, though I did work on Google Docs.
For Linux, it depends.
If it's my local PC, I'd use Sublime Text 3 and the Ubuntu text editor.
For the server, though, (aka Debian 9), fuck the text editor that comes with it. I'd rather get nano.