I am a non-resident and file taxes manually by mailing the return. I have completed return but forgot to input my T3 an dT5, how can I regenerate my return from TurboTax?

Hi unfortunately you will not be able to re-file using Turbo tax.  You will have to log into your myCRA account and on that site in the menu option you will see an option to re-file.  You can select the slips you missed and submit the information there.