The Apple Watch Series 6, released in September 2020, is the current iteration of the Apple Watch that was originally launched in 2015. The Apple Watch Series 6 is identical in design to the Series 5, but there are some notable health-related features along with a faster chip for better performance.
Probably you will learn these from this book:
Guides for User: Master Apple Watch 6 and WatchOS 7
New Features for Users: What Makes The New Apple Watch Series 6 Special?
Apple Watch Series 6: How Do I Set Up A New Features