In the circumstances where a return is not accepted by NETFILE/EFILE, for instance, a final return for deceased, you may need to print and mail a paper return.
Before you go to "File your Returns" page(second picture) to download and print the return, you need to go to Submission Settings page to mark the return as paper-return.
You also need to sign the return and attach the supporting documents like T-slips. You can find the mailing address that serves your area by clicking on this: CRA ADDRESS
You also need to sign the return and attach the supporting documents like T-slips. You can find the mailing address that serves your area by clicking on this: CRA ADDRESS