I just upgraded my iCloud but it isn’t working

Go to Settings><your Apple ID>iCloud. It should say right there what plan you are on. The page with the graph will show Storage, then iCloud+ and how much is used and the total you have. If you haven't, try restarting your iPhone. Next question, is what kind of video were you trying to save? What did you see on the screen when you tried to save it?

What exactly is not working? You need to clearly explain your issue.