I"m filing my 2020 taxes via Turbo Tax. It's asking for line 23600 but such a line does not exist on my T4. I know it's Net income, do you know what line I need to use?

Line 23600 is found on the T1 General, not on the T4 slip. You can see Line 23600 in TurboTax Online by looking at your Detailed Tax Summary or by downloading/printing a copy of your 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?