Port forwarding is a function of NAT. It’s only needed because there aren’t enough ipv4 addresses for every device, so in most networks a lot of devices share a single ip and specific ports are forwarded to specific internal hosts

IPv6 has a large enough address space that this isn’t needed. You can still do it if you want. But mostly you just need a firewall without any NAT.

There’s more to it than this but you should get the idea.