Permanent residents (PR) of Canada must carry and show their valid permanent resident card (PR card) or permanent resident travel document (PRTD) when boarding a flight to Canada, or travelling to Canada on any other commercial carrier.
In addition to your passport, you may need a travel authorization such as a visa or an Electronic Travel Authorization (eTA) to enter Canada. Consult Immigration, Refugees and Citizenship Canada's website to learn which authorization you need: Find out if you need a visa to travel to Canada.
A travel document will only be issued if you can demonstrate to the immigration officer that you meet or will meet the physical residency requirement to maintain the PR status. Depending of the office, issuance of a travel document can take a few days to a few weeks/months.
If you're outside Canada without a valid PR card, you need to apply for a permanent resident travel document (PRTD). A PRTD is normally only valid for one single entry. You should apply for a new PR card as soon as you resume residence in Canada.
A travel document will only be issued if you can demonstrate to the immigration officer that you meet or will meet the physical residency requirement to maintain the PR status. Depending of the office, issuance of a travel document can take a few days to a few weeks/months.