How can I upload my personal song to Apple Music for downloads with my Android phone?

Are you wanting to publish your song for others to download via the Apple Music store? Or just transfer your song so that you can play it?

Apple doesn't allow arbitrary song uploads from individuals. You'll have to go through a music publisher in order to get your song in the Apple Music Store. Check out https://distrokid.com/ as one option (there are others).

If you're just trying to transfer the file, then any file transfer mechanism should work, including just emailing yourself a copy of the file.