What OS are you using?

I am using windows 10
On laptop windows 8.1

Mostly MXLinux (Debian based) with IceWM

I'm using Linux Mint and Windows in a dual boot setup.

Windows 10 pro on my personal computer, otherwise Linux (Centos, Ubuntu, Debian)

Currently on MacOS Big Sur for work & Windows 10 on my personal computer!

I am using windows 10 Pro, Debian 10, Centos 7, Kali Linux(PenTest)

I use both Linux and Windows

Windows 10 on personal computer, Ubuntu 16 on work computer.

windows xp obviously...

I have everything, I have a server that is running Linux, windows on my desktop, a Mac laptop then I use Android on my phone.