About TextEdit version 1.9

1. There is at least 1.12 dating 2016.

2. There are other, search in AppStore. At least, you have Pages

3. It all depends what you want to propose to users. Look at TextEdit, Pages, … and think to what you want (not just mimic those apps)

The version of TextEdit that ships with macOS 10.12 is version 1.12, but it's possible that 1.9 is the latest version for which source code is available.

In macOS "document application" usually means an app that relies on NSDocument functionality, but it sounds like you mean a word-processing application, or something along that line. If so, I'm not aware of one provided by Apple other than TextEdit. You can try searching on (say) GitHub for 3rd-party alternatives.

Note that NSTextView is a very full-featured control that implements a lot of very sophisticated text editing and layout. That might be a better place to start than to look for an entire app. The NSDocument (i.e. file handling) parts of the app are more or less independent of the text editing parts.

Also keep in mind that TextEdit has been around since 10.0, and has been rewritten numerous times, but its code does not necessarily represent the current state of the art of macOS programming. IMO you should think of TextEdit as a showcase for NSTextView and NSDocument, not an actual starting point for your own code.

Sorry...

Usually when discussing apps here at apple developer, it's implied I am referring to the source code.

BugMage

In approximate terms, 50% of TextEdit is a standard NSTextView, and 25% is standard NSDocument behavior, which can use too, but you won't get to see source code. The other 25% is TextEdit's specific UI code, more or less. It may be a good reference point, but I doubt you'd want to use it directly.

(in response to Q)

It is probably a good idea to start from scratch. I do not need the full functionality of the TextEdit code yet at the same time, TextEdit may be a template style to imitate.

Thanks