Right now, Microsoft does not offer regular customers to purchase the ARM version of Windows 10, unlike the other x86 versions of Windows 10 like the Home and Pro versions. Right now, Windows 10 on ARM is only available to computer makers, although users can download the Insider Preview build which is obviously not necessarily meant to be used as a daily driver.
This means that even though the latest version of Parallels Desktop does support Windows 10 on ARM, getting a copy of the software will prove difficult. We’re not sure if Microsoft ever plans on making Windows 10 on ARM a purchasable copy like Windows 10, so we’ll have to wait and see.
In the meantime, like we said, you can always rely on the Insider Preview, or if you’re a bit more adventurous, you can also check out Linux distros such as Ubuntu, Kali Linux, Debian, and Fedora Workstation.