Here is how view and print old returns:
Log into your account
Select the Taxes tab
Select My Tax Timeline (see screenshot) then select the year you wish to view
Select Download/print pdf return for the 1040 or Download all forms and worksheets to print all forms (see screenshot)
If you haven't yet paid your TurboTax Online fee (or registered, if you're in a free version), you'll need to do so before you can print.