itch.io

in godot you export to web by adding the Web template on the export window (same window you added Windows template) to.  Then you export the Web stuff to its own folder,  change the HTML file to index.html, zip that folder up, and upload the zip to Itch 

and for sound, you can drop in an AudioStreamPlayer node on the main game (for music) or the player/enemy/projectile scene (for object-based sound effects).  And there are some free asset libraries out there with sounds in them