Where's the path to browser-accessible content with Hass.io

I’m trying to serve doorbell.mp3 to media devices. I can’t figure out where to store it on Hass.io to make it reachable. I’ve tried
HASSIO-ADDRESS/doorbell.mp3
HASSIO-ADDRESS/local/doorbell.mp3
HASSIO-ADDRESS/www/doorbell.mp3

I’ve also tried creating a www folder within my config folder in conjunction with the above URLs, with no luck. I get 404s for all options.

Looks like you need a restart after creating the www folder.
After restart it worked for me with:
http://HASSIO-ADDRESS:8123/local/test.txt

Thanks. Yes - a restart did the trick.