zdnet[.]com/article/when-will-you-get-the-next-version-of-windows-10/
If you're running win10 v. 1903 [the Spring 2019 version] it's not a big deal -- this time 'round we're getting a cumulative update, rather than a complete new version install. If you're running last year's spring version [1803] you won't have much of a choice, but if you're running the version released last fall the upgrade is an option -- in each of those cases you'll be going the full upgrade/install route. This article from ZDNet's Ed Bott talks about how to tell which version you have, & getting ready, being more in control of the update process.