You need a Social Insurance Number (SIN) or an individual tax number (ITN) or a temporary tax number (TTN) to file a Canadian tax return.

This webpage tells you how you can apply for a SIN number: https://www.canada.ca/en/employment-social-development/services/sin/apply.html

This webpage has a form to fill out if you need to apply for an ITN instead: https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/t1261.html

If you are trying to prepare a US tax return, then please visit our US site here: https://ttlc.intuit.com/