You have to apply for the SIN application and getting a number takes a short time provided all the relevant documents required are presented. Please see the link below:
https://www.canada.ca/en/employment-social-development/services/sin/apply.html
You also have to file the tax return for the 2022 year and you can’t use NETFILE to file your tax return if you are filing an income tax and benefit return for the first time with the CRA and the CRA does not have your complete date of birth on record. So most people filing for the first time do have to mail in their returns.
You can file your tax return via mail as a first-timer and without a SIN as per CRA see the link below:
https://www.canada.ca/en/revenue-agency/services/tax/international-non-residents/individuals-leaving...
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