You can also search for 'Catalina' in the store if you don't see it.
If Catalina is available, you should see the new OS listed. The update icon at the bottom there corner of the movie tells me I mojave an exclusive to install, but doesn't work me if it is the unecessary Tammy update, so each transaction I mojave to click on screen to be sure it's not download. It featured a new brushed metal interface, an updated Finder, and many more features from Jaguar the year before.
