corp is the confirmation document that you you will receive from the immigration Dept, it proves that you through the Permanent resident process. Now you will have to present that document along with your passport at the Canadian Border Services Agency(Canadian Border)...to complete the landing.
You don't need to send your passport if you're from a visa exempt country. They sometimes
ask for as scan of the photo page, but that's it. The CoPR then has to be presented at the POE to complete the landing.
If you already received your COPR you need to exit and re-enter Canada in order to land as a PR (using your COPR). You can also do it in a local CIC office.