Upon the expiry date, CIRA will automatically renew your .CA for one year, charging your registrar. You will need to renew the domain with your registrar if you want to keep it. Your registrar has the ability to cancel this renewal, if you haven’t renewed the domain with them.
Expiry dates for .CA domains can be found by searching WHOIS. If it’s past your expiry date with your registrar, you will notice that the WHOIS record for your domain has changed to one year after the expiry date.