Setting up a public IP address varies dependent upon your Internet Service Provider and router, and it may be best to get in touch with them about the best option for you. However, generally for home internet, port forwarding is common to expose a host via the router's IP address. There is an older forum post that touches on this, that I'll include here:
I was also able to find this general guide on setting up port forwarding on a router:
Hopefully this helps!