You can print out a PDF of your return and upload any required forms. Please refer to this link: How do I print a copy of my tax return in TurboTax?

Thank you for choosing TurboTax.

I do not need to print out a PDF of my return I know how to do that.  I need to attach supporting documents when I NetFile, as in previous years CRA has asked that I provide proof of payment/invoice for childcare expenses.   Am I able to attach supporting documents when I NetFile?

No, you can't add supporting documents through NETFILE. If the CRA needs additional information, they will ask, and they will give instructions on how to send them the needed documents.