I don't see how this applies to you. If you received an email that said "Congratulations, you are now a permanent resident of Canada," you are a permanent resident of Canada and require a PR card or PRTD to board a plane. As a permanent resident, you have the right to enter Canada, it's just your carrier who will deny you boarding if you can't prove your PR status. Your COPR is not a travel document, thus it won't prove your PR status to the airlines. Alternatively, if your work permit and TRV are still valid and they were approved before March 18, you can board the plane showing them that, once you land in Canada, you can show the CBSA officers the COPR or the document you received in your email. If you want to be on the safer side, apply for a PRTD and have it with you when you board the plane.
Edit: I saw your earlier posts and I can definitely tell you that you need a TRV or a PR card or a PRTD to board the plane to Canada. Indians can't apply for ETA and ETA is just for temporary residents.