If you simply want one TV to propagate all the way down a chain of documents, just use
... as the default value of your TV, and you only need to fill in the one in the very root doc of that folder. (and obviously the other documents in that folder must also use a template that has access to that TV). Your value will automagically show up in all child documents.
But what if you just want to update one little place and have it go absolutely everywhere exactly the same? Then just use that TV in every template and simply change it’s default value to whatever. You could use a chunk the same way. In both cases, you’re editing the TV itself in the Manager, not editing a document. Not great for clients though, and some HTML editing probably needed....
I scratched my head one day and came up with a cute way to make it possible for even a client to manage it. No TV’s, instead you use Ditto. Make a doc somewhere not in the menu, and label it "Edit Me to Fill in the Red Box" or whatever. Then you make a Ditto call which pulls in this document into all your templates. Your Ditto template will have nothing in it but
... unless you want to format it somehow. Then your client can edit that one doc, and have it show up absolutely everywhere, without much fuss. My cohorts were delighted with that one.
is Revo syntax, if memory serves, btw. You might have to read up on Ditto, or look at example calls.