Can you upload your own music into ” My Music”?
The answer is yes you can . You have to download the My Music App from Amazon but that allows you to have an interface that collects any music you have bought from Amazon and then you have a import and upload facility which is not available within the Amazon Music browser.
In order to test this I download a music file via Groove and the Microsoft store. I am sure I could have used iTunes by going into the file structure of iTunes and choosing iTunes Media and the relevant folder.
Having loaded the file or files(s) you can even upload folders I then was able to say to Amazon Echo Dot:-
“Alexa, play <name of song> ”
It then says “Playing <name of song> from your music files”