The teleprompter is a simple passive device that clips onto a monitor with a popup or clip on webcam. The teleprompter reflects a 6x4" region of the screen directly in front of the webcam. You can look into the camera to read text or make eye contact with a video conference. It does not noticeable change the video quality recorded from the webcam.
The provided STL files were designed to fit my Dell OptiPlex 7760 All-In-One, but the editable TinkerCAD design is available so you can tweak it to better fit your monitor.

I wrote a completely free HTML/Javascript version of a teleprompter app, and included the source code for those interested in changing it...
https://hackaday.io/project/178618-entirely-html-simple-teleprompter