Permanent residency(PR) is a person’s resident status in a country of which they are not citizens but where they have the right to reside on a permanent basis. When you are boarding a flight to Canada you must carry valid PR card or PRTD ( Permanent Resident Travel Document). The Permanent Resident Card (PR Card) is the official proof of your status as a permanent resident in Canada.
A person in Canada temporarily, like a student or foreign worker, is not a permanent resident. To keep your permanent resident status, you must have been in Canada for at least 730 days during the last five years.