Once the PDF has been downloaded to your computer, you can view or print the return with any PDF compatible viewer, such as Adobe Reader.
You have to sign onto your TurboTax online account with the exact same userid and password you used to create the account.
If you may have forgotten some of your login information, see the following TurboTax support FAQ -https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-user-id-or-password
Or you may have multiple accounts, see this - https://ttlc.intuit.com/questions/1901486-problems-associated-with-multiple-turbotax-accounts
If you receive a message that your tax return is Locked or that you need to pay for the account, see this TurboTax support FAQ - https://ttlc.intuit.com/questions/2926523