When you have a computer, you have hardware which is the box in front of you but on that box you can install different software. E.g. windows, macos or Linux.

Linux got its name from Linus Torvalds who was what I'll say the architect and substantial worker of the kernel, ther very core of the operating system

The computer has a few layers. If you write a program, it may do something like let you read emails,but this program is at the top layer and when you do something like save a picture to your desktop, it tells the operating system that the email attachment is to be written to the disk.

Now the hard drive of the computer is managed but the operating system, and the operating system negotiates with the hard drive on where to actually store it on the hard drive.

In a sense the operating system is like a person you give a photo to and say file this away for later.

That person was there when you got the hard drive/filing cabinet and keeps track of what sin which draw and in which removable folders.

Later when you ask the operating system to show it again, it goes back to the filing cabinet and gets the picture without you or the email program having to know the nitty gritty of it was in the 2nd draw , nearly all the way up the back.

The operating system also does thing like operate a the WiFi a bit like a radio and schedules when tasks run on the computer.

Im stretching the analogy here but imaging an office where only one to four people work there. the operating system keeps track of all the things they need to do and make the system function well.

Microsoft made Dos (disc operating system) and windows. Apple made Macos , a long time ago on early mainframe computers there was Unix and Linux is an operating system originally made to replicate the look and feel of Unix.

But it's build under an open source licence so you can download and see all the internals and change them if you want.

Android phones and tablets run Linux.

It's versatile and can be adapted. I've got some 10 year old computers I've reconfigured as a server running Linux that wouldn't be able to run modern windows operating systems.

Edited to add People make up different distributions like flavours of Linux.

Debian is a version which is old and stable. It's not bleeding edge, but their releases are tried and tested.

Ubuntu is one which Ive bee using for a while and I'd call it user friendly.

Gentoo is a distribution which the installation compiles it's source code optimized for each computer it's installed on to be as fast as possible.

Kali is a distribution focusing on network security.

Arch is another distribution.

I hope it helps.