iOS 16 makes a number of welcome tweaks to existing features that streamline things while making apps like Maps, Messages and Mail more powerful. These aren't big changes, but they add up to a better iPhone experience.

To install iOS 16, you'll need an iPhone 8 or later. That covers any iPhone released in 2017 and beyond. That eliminates a few devices capable of running iOS 15 but left out in the cold with iOS 16. All iPhone 6s and iPhone 7 models can't upgrade to iOS 16, nor can the original iPhone SE.
The SE 2020 and 2022 versions are supported, however.

The iOS 16 release candidate is a stable, polished version of the beta we enjoyed over the summer months. That said, OS releases only get more stable with time, so you don’t need to update your phone right away, especially if you’re comfortable using iOS 15. However, iOS 16 includes many new, impressive features that you might find enticing.

Unfortunately, some features aren't compatible with all phones. For example, Live Text and Visual Look Up are only available on the iPhone 11, iPhone 12, iPhone 13, iPhone 14, iPhone XR, and iPhone XS. Likewise, the new Dynamic Island feature is exclusive to iPhone 14 Pro and Pro Max.

iOS 16 Features

• Lock Screen customization and widgets
• Live Activities and Focus filters
• iCloud Shared Photo Library
• Passkeys and Shared Tab Groups
• Live Text, Visual Look Up, and Dictation Enhancements
• Updates for Messages, Mail, Home, Health, Wallet, Maps, and more
  
  

Looking for in-depth review on the newest features click the link below 

https://www.macrumors.com/roundup/ios-16/