Due to copying errors, mistakes are accumulating in the genes of the virus. It's a relentless process of trial and selection. A trillion monkeys on keyboards blindly working its way around vaccines, and immune systems. To beat this, we need to understand it.
Below is a map of known variants created from the samples which have had full sequences done. This is the remarkable "Nextstrain" — an opensource tool. I have labelled a few clusters by their "country names", (though we're not supposed to do that. Let's all say "WuFlu".)
The family tree of SARS-Cov-2 starts at the bottom left corner with two samples from Wuhan around Christmas 2019. This is called the 19A clade, which appears to have almost died out now, though there are still remnants left of this original virus in corners like Iran and PNG. Otherwise, the Wuhan 19A virus has been superseded by its children.