Hi Heather, Windows 12 is an Internet myth, there will be no Windows 12
When support for Windows 8 ends, Microsoft will re-brand Windows 10 to just Windows
The model Microsoft are using going forward is, twice yearly a new version of Windows (called a Feature Update) will be released. That feature update will include any new Functionality and features available for Windows and will deprecate older features
That way, once your PC is up to date, you will always have the latest version of Windows. This is something like the Office 365 model, with the one exception, Windows 10 feature updates are free and there is no subscription .