I don't think this info is quite as clearly explained by apple as it should be. What they say on their website at https://www.apple.com/macos/catalina-preview/ is What they don't say is that this is a feature that is something that has to be manually enabled before it will work. And what is worse is that they don't even explain how to enable it. So if you go ahead and do exactly what apple say - hover over text and press control - nothing happens! Because you didn't enable it! Because apple didn't tell you to enable it! (or for that matter how to enable it). Anyway, rant over. Here's how to enable it. In the Finder menu follow through -> System Preferences... -> Accessibility -> Zoom Then tick Enable Hover Text as follows: And by the way, it's ⌘, not Control.