Another user already gave you the answer, but one thing to bear in mind is that Cloudflare only “speak” HTTP(S), and nothing else. So if for example you want to run Minecraft, CloudFlare’s free plan will not allow you to route it through port 80/443 as they don’t know how to “speak” the Minecraft protocol.
Also, could a reverse proxy be used to give cloudflare’s services to a port they don’t support?
Another user already gave you the answer, but one thing to bear in mind is that Cloudflare only “speak” HTTP(S), and nothing else. So if for example you want to run Minecraft, CloudFlare’s free plan will not allow you to route it through port 80/443 as they don’t know how to “speak” the Minecraft protocol.