macOS Sierra (version 10.12 ... the update will be available free of charge from the Mac App Store, just like past versions of OS X.

I was able to have Siri adjust screen ... OS X El Capitan remains, and virtually all the enhancements found in macOS Sierra are effective and useful. Oh, and did I mention that it's free? Mac ...

Apple made a major change in their security & privacy settings with OS Catalina and above, making screenshare/screen record feature a manual setting, defaulting to off. You may need to tap the lock ...