Embassies and consulates by destination
https://travel.gc.ca/assistance/embassies-consulates
Government of Canada – Consent letters for children travelling abroad
https://travel.gc.ca/travelling/children/consent-letter
Government of Canada – Invitation Letters
https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/letter-invitation.html
Government of Canada – Authenticating Documents
https://www.international.gc.ca/gac-amc/about-a_propos/services/authentication-authentification/step-etape-3.aspx?lang=eng