Most Ubuntu based operating systems are quite easy to use. I recommend using the xfce version for distributions. They are the most familiar, although some of the other desktop enviroments are pretty good. Use a REL, Debian, or Arch based system for best application compatibility. I recommend Zorin, because it is the cleanest and uses native application pictures. Mint is great for older people, but it is quite old fashioned looking. It kinda looks like older versions of Windows. Ubuntu is not bad, but it is not very similar to Windows, but MacOS, with the side bar config. KDE enviroment is not too bad. I think you should try out all the versions. Most distos on the Download Linux page is quite good and are generally supported. Any Ubuntu based distros benefit from askubuntu.com. For beginners, I would say Pop OS, PureOS, Ubuntu, Xubuntu, Zorin, MInt, and Manjaro are a good bet. However, just find a good distro for you. It might take some searching.