If I NETFILE my return, do I have to mail-in any paper slips or supporting documents?

If you’ve chosen to NETFILE your return, you won’t need to mail-in any of your forms, tax slips (T4, T5, etc.), official receipts, or any other supporting document unless the Canada Revenue Agency (CRA) or Revenu Québec asks to see them.

Note: As a rule, the CRA recommends that you keep all your tax information (including slips, official receipts, bank statements, and canceled cheques) for a minimum of six years once you’ve filed your return.