For now (early-early acces) you can distribute just .rar (or .zip) of your files. I don't know what engine do you use, but Unity for example compile everthing to single folder, so you just "zip it" and post it hire. Trust me, instaling something from someone you don't know is not good idea. Also you can do web build and upload your game directly to itch.io so anyone can play it without even download