Thanks for all the help, even though I got my terminology mixed up.
Yes, I want to download the actual file, which apparently is an .azw and not a .mobi as I thought, to the PC. I want the actual file itself. Simply "sending" it to Kindle for PC is not my goal here. I want to have the actual file; the actual book. Whether it has DRM or not, I bought it and I want to have it in my folder with all my other books. I don't need Amazon to safeguard it from me, since it's mine.
On the Android, I looked under files/kindle/azw and it's unfortunately empty, even though I already have numerous books on there. Strange!