Apple released a range of updates for iOS, watchOS, and tvOS today, all three of which have been in beta for some time. As usual, iOS 13.3 and iPadOS 13.3 pack the widest range of features.
The main new features for iOS include Screen Time improvements, letting you set parental controls on which of your kids can use things like FaceTime and Messages, and you can also decide which contacts they can call. Apple News+ is also getting a new layout for "leading newspapers", and there are also some improvements to Stocks. Of course, there are also fixes and improvements.
As far as watchOS 6.1.1 goes, that's all about bug fixes and improvements, and there are no new features. That should be indicated by the version number.
Finally, tvOS 13.3 isn't big on new features, but it does allow you to add the "Up next" queue to your home screen. You'll be able to switch between "What to watch" and "Up next", as noted by 9to5Mac.
All of these updates are available now, so if you've got automatic updates turned on, they'll just get installed overnight.