https://techcrunch.com/2018/09/17/ios-12-is-now-available-to-download/

Apple has just released the final version of iOS 12. This update is all about making your phone work better — and there are also a bunch of new features. The update is currently rolling out and is available both over-the-air in the Settings app, and by plugging your device into iTunes for a wired update.

Many people try to download these major updates at the same time. Apple usually implements a queue system to ensure speedy downloads once you’re at the front of the queue.