To display a chat message on your screen, you will need to modify what people see when you are sharing your camera.
To add something to our screen on Zoom we need to use an app that will intercept our camera image and modify it live. There are different apps in the market that can do this, but the most powerful one when it comes to designing interactive live experiences on Zoom is OBS, which is what we are going to be using.
Download OBS: [https://obsproject.com/](https://obsproject.com/)
(It is free and works on Mac and Windows)