It is the purpose of ISPConfig to host own domains, but you register them at a registry like 1&1, godaddy, etc... I guess you dont now what registering own domains means. E.g. in germany you must become member of the denic e.g. and pay about 50000 EUR to become a registrar. For .com domains you will have to pay much more. Or you must have a reseller contract with one of the large registrars.
You can register thousands of domains with one IP and use them for websites. But you can have only one SSL secured domain on each IP.
