Moved to the scripting forum....
var _text = 'Welcome!'; app.activeDocument.textFrames.insertionPoints.contents = _text;
If your "cursor point" is a selected text insertion point or selected text then simply do:
app.selection.insertionPoints[-1].contents = "Welcome";
But maybe—I'm not sure about that—you want to load text to the placegun?
Then you could create a text document first and load that to your placegun.
If there is no text highlighted (you just have the flashing 'cursor point' then that can be referenced as the selection..
app.selection.contents = "Welcome";
You seem to move a lot of posts..
They should make it to where members can choose which forum would best fit their question.