Who do I need to tell that I have moved?
Your driver's licence and health card within the statutory window, the Canada Revenue Agency, your bank, insurer, employer and pension, plus the municipality for property tax and water. Add a Canada Post mail forward to catch the rest.
The ones with deadlines: Ontario requires you to update your driver's licence and health card address promptly after moving, and driving with an out-of-date licence address is an offence.
The ones with money attached: the Canada Revenue Agency, because benefit and credit payments and your assessment follow your address on file. Your bank and any lender. Your insurer, immediately, because coverage on the old address does not cover the new one. Your employer, for payroll and tax.
The ones that create arrears if you forget: the municipality, for the property tax account and water billing. Do this in the first week so the first bill arrives at the right address rather than becoming a surprise with interest on it.
Then everything else: pharmacy, doctor and dentist, vehicle registration, subscriptions, and any professional body. A six month mail forward with Canada Post catches the ones you missed, which is always more than you expect.
Next questions
What should I do in the first week after closing?
Change the locks, find and label every shutoff, test the alarms, confirm each utility account and its start date, and photograph the meter readings. Then leave the renovations alone for a season.
Ontario
How do property tax bills work after I buy?
Settle two things in your first month: what your municipality's own payment schedule is, and whether your lender is collecting property tax with your mortgage payment. Either you pay the municipality directly or your lender remits it, and assuming wrong creates arrears.
Ontario