Handling dialogue-like situations

I’m writing a screenplay where a magical typewriter communicates to people by typing them messages. Nothing verbal. Since this will be a selling script is ok to put in a note saying this, then proceed as…

Or is there another way to do this? This type of communication will exist through the entire story.

— Harry
Detroit

Since the typewriting is “speaking” dialogue, your way is fine. If it only happened once or twice in the script, I would be tempted to put the typing in boldface, centered on the page. But that would get really annoying, really quick. For what you’re attempting, faux-dialogue is best.