To see past years' tax information (all years you've filed with TurboTax, not just last years), you need to:
1) Login at: https://myturbotax.intuit.com
2) In the navigation menu at the top of the screen, move your mouse over "My TurboTax", and then click on "My Tax Timeline".
3) If you scroll down on that page, you should see a list of all prior tax years' information. And you should be able to e.g. Amend (change) returns, Download/print return (PDF), Download .tax file, View adjusted gross income (AGI), View order details, View eFile details.