The federal government is expected to announce a relaxing of border restrictions for those who are fully vaccinated. Because it is not yet known when formal "vaccine passports" might be issued or exactly what form those will take, the government has said it will be relying on the provincial vaccination certificates which can then be uploaded to an app called ArriveCAN. More details on that will be coming soon.
If you misplace a vaccination receipt, you can login to the provincial booking system and download or print another copy.
To log in and get your receipt, you will need:
a green photo health card(you will need numbers from both the front and back of the card, expired cards will be accepted)
your postal code (the one associated with your health card)
your date of birth
More information can be found here.