No. When you file your tax return through NETFILE, you do not have to submit your receipts, information slips or other supporting documents to the CRA or Revenu Québec.
But, you need to keep this material safe and available in case the CRA or Revenu Québec request at a later date to see supporting documentation.
The CRA advises that you should keep your supporting documentation for six years. Read more about how long you should keep your income tax records.