To allow people to access from the internet you need to forward the ports on your router to the internal IP of the server for the services that you are running.
Then you need a domain name, so people don't have to remember IP addresses. As you say you have a dynamic IP then you will need something called a Dynamic DNS, this you can get for free from one of the providers that moonlit has provided. You install their software and it will make sure that the domain that you get from them always goes to your current IP.
You can then buy a domain yourself and forward that domain to the domain you get from your Dynamic DNS provider, so you can have something like xyz.com rather than xyz.no-ip.com.