Change pre-installed services like "Take Plain Note"

Is there a way I can change (or duplicate) the way services like “Take Plain Note” work? I couldn’t find separate .workflow or installed Services somewhere, but I’m not sure if that’s at all possible or maybe someone has already rebuilt some of them as Automater / .workflow packages?

Change in what way?

E.g. I want to precede the added text with a "> " (amongst other things)

Services are not customizable, a smart rule and a script could post-process the notes though.

I suppose you could write your own service (using Automator while it stil exists) that does what you want.

Thanks @cgrunenberg @chrillek that’s what I’ll do then: build my own Automator workflow (or use Shortcuts). I was under the wrong impression Services would also be editable like scripts, but this approach would work too. Thanks.