I am paying 236 rupees inclusive of GST for a public IP address. They ask for your MAC address to which they will bind your Public IP. While you don't have to do anything specific from your side to switch over to static IP you can manually configure the IP. I have it left is PPPoE mode in my OPNsense firewall and it seamlessly migrated from dynamic NATed private IP to public Static IP. I can confirm that all ports are open both TCP and UDP including 80 and 443.
It actually depends on the location. Following is my personal experience.
1. In one location i have ACT coming through ethernet. Here my experience was similar to @retionac above. I continued to use PPPOE was before. No change was needed.
2. At my second location ACT brought in a fiber to the house and set up a ONU. At this location the asked me to setup the static manually. They told pppoe is not supported if you have a static ip.