If you are using an older version of macOS and are ready to update to a newer version, the first step is figuring out which versions of macOS your Mac can use. Apple provides compatibility information for each version, and you can find them all at https://macmost.com/j-system as well. If you are looking to downgrade or to upgrade to a version not supported by your Mac, I have some general advice.
There are a few new features in macOS 11.1 you should know about. There are new News app widgets, a new default search engine option in Safari, and improvements for running iOS apps on M1 Macs.