was is possible to use PC as host for website I mean a user on web can write the url or my IP and access my web ?
If people access your IP directly, yes, they will be able to see the site. However, if you run behind a router, you will need to port-forward port 80 on your router to the box that hosts the IIS server. Detailed guides for how to do this are available at your router manufacturer's website, or more conveniently, at portforward.com. In most cases, your consumer-grade ISP is going to have restrictions on what ports you can have open -- many filter incoming HTTP connections and would prevent you from running a server this way.
Note that if you're running this at home, your IP is probably dynamic and will change over time, so the IP address you give out today may not be valid tomorrow. Try looking at a service like dyndns.com, which maps a dynamic IP to a static hostname.
To use a fully custom host name will require that you tell your DNS provider how to resolve requests for the host name you want to use. For instance, if you want
example.com to map to your box at 188.8.131.52, you need to tell your DNS registrar to resolve requests for
184.108.40.206. The exact steps to follow will depend on your registrar and a number of other factors, so ask your registrar's support email.