TurboTax Online doesn’t have a forms mode like TurboTax CD/Download. However, you can still see key T1 line numbers by looking at the Detailed Tax Summary. You can also see your actual tax forms by downloading/printing a copy of the return.
Please see the following TurboTax FAQs for instructions:
How can I see a detailed summary of my return in the online edition of TurboTax?
How do I print/save a copy of my return in TurboTax Online?