The answer to this depends entirely on what you’re looking for in an OS.
Beginner users are encouraged to check out Ubuntu and Linux Mint — these are the typical starting points for newbies, with intuitive interfaces, tons of dependable software, and a look and feel pretty familiar for Windows and Mac users.
I personally like Ubuntu. It’s got built-in Linux security like AppArmor and a ton of secure files on its software repository. That said, in order to stay 100% secure, I still needed to harden my machine with several antivirus tools like a malware scanner and a sandboxing program.
I recommend that anybody who truly needs a secure system — like coders, journalists, activists, and lawyers — check out QubesOS. I installed it on a Dell laptop, and I was really impressed with how it partitioned different functions on a single computer — it makes it virtually impossible for a hacker to gain access to important files.