Where will I get text editor? Is it an app or it is a component in freecodecamp site?
It is unclear which lesson you are talking about.
Most computers come in with built in text editors and there are many free ones for programming, depending on your system.
Everyone has their own favorite text editor, so to make this easy: just download Sublime Text and see how you like it. It’ll require a little setup to get it just how you like it, but it’s usable “out of the box” before you figure out all the configuration options and packages available.
VS Code is my favourite one.