Linux is a computer operating system similar to Apple’s OS and Microsoft. It is free, but although you can usually get it without cost, the important thing is that it is free of limiting copyright restrictions1. You can get it from anyone and do anything with it without incurring the wrath of big companies or encountering limitations deliberately designed to make things difficult for you.
1 There are limitations but they are designed to prevent anyone from introducing restrictions, so you can do pretty much what you like with it as long as you acknowledge where it came from and don’t limit future users.
It is free. It is secure. It is fun. It is powerful. It is easy to install and to replace. On the very rare occasions when something goes wrong you can simply bung in another copy and carry on. It runs on cheap hardware. The applications that go with with it are legion, excellent and also free. I can’t actually think of any reason why anyone would use anything else.2
2Actually I can: Linux is not often pre-installed and you will need to find a copy and learn how to get it and install it. Also there are a few proprietary applications, and pieces of hardware, that you may be using that are dependent on one of the closed operating systems. If these are a problem to you it is worth seeking help and advice to wean yourself off of proprietary things that don’t work and take the plunge.
https://distrowatch.com/dwres.php?resource=major is worth look
https://distrowatch.com/dwres.php where you can buy a flash drive ready to install and will not need to do it ever again.
https://distrowatch.com/dwres.php?resource=major gives a good summary of what is available and advantages and disadvantages.
Android on most portable devices is a version of Linux.
