Citizenship and Immigration Canada issue the Permanent Resident or PR cards for its citizens. PR cards serve as proof of identity for people departing from or returning to Canada by any means of transportation. You may not be allowed to enter Canada without a valid PR card.
You are issued a Canadian PR after getting permanent residency certification. Permanent residents with landing documents need to apply at through Canada Immigration (CIC) for PR cards. The validity of a PR card is 5 years and it is required to travel in Canada after returning from abroad. It is mandatory to renew your PR card after expiry.