I just wanted to try to clarify this issue since it still seems to be causing confusion.
You seem to be under the impression that "inserting text at the cursor anywhere in the system" is a built-in function of Opus.
It's not.
Opus does not have a function like that. That's a function of something like AHK.
The one way you can do it through Opus, which is what the thread Leo pointed you to described, is to use a bit of scripting to use the WScript object's SendKeys method to generate key presses.
(The WScript object is also not part of Opus. It's provided by Windows.)
When a text field is active, generating key presses (which makes it appear that you are typing on the keyboard) has the effect of inserting text at the cursor position.
So if you really want to do this through Opus, instead of AHK, you need to take the scripting example that Leo pointed you to, and adapt it to send the key presses corresponding to the text that you want to insert. You then need to set it up on a system-wide Opus hotkey so that pressing that hotkey when Opus is running triggers the script.
But again, and I can't stress this enough, this is not a function that Opus has built-in, it's not something Opus was designed to do, and if you expect it to be possible through a "one word command" you're going to be disappointed.