Replit is an amazing tool. Big fan. But currently, you can't deploy a simple HTML project, which is just baffling. Let me throw my index.html into the void!
There's an easy solution, though. Use Replit's Shell tool and run npx surge. You'll need to select a node version, and then set up an account with Surge.sh which will let you manage your deploys. Surge will assign you a random domain, but you can change it to whatever you want.
You can also run echo your-domain.surge.sh > CNAME to create a file at your project root that will tell Surge what domain to deploy under.