Parked Domains allow website owners to point additional domain names they own to their site. If sample.tld owned test.tld, Parked Domains would allow the owner to point test.tld to sample.tld. All of this can be done with one simple form.
Parked Domains will also allow a website owner to point an Parked Domain to a directory of the main domain. This would mean test.tld could point to the sample.tld/test/ folder.