On Windows: VirtualBox (free and easy to use, but still advanced/powerful) or HyperV (already included if you have Windows Pro).
On Linux: anything based on KVM, my personal favourite is virt-manager, but QEMU is also great.
I would stay away from VMware because the free version is quite limited, and the pro version is not free. The free alternatives are equally good or better, so no reason to use something paid imho.
On Windows: VirtualBox (free and easy to use, but still advanced/powerful) or HyperV (already included if you have Windows Pro).
On Linux: anything based on KVM, my personal favourite is virt-manager, but QEMU is also great.
I would stay away from VMware because the free version is quite limited, and the pro version is not free. The free alternatives are equally good or better, so no reason to use something paid imho.