If you are using the TurboTax desktop CD/Download editions, all saved tax data files and saved PDF's are stored, by default, in the TurboTax folder in the Documents directory.
If you are using the TurboTax online editions, To access your current or prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
If you have multiple TurboTax online accounts then follow the instructions in this TurboTax support FAQ for how to view your accounts - https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/many-intuit-accounts-turbotax/L9aVfKS1Z_US_en_US?uid=ll5g6zcx
If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created. TurboTax does not store online any returns completed using the desktop editions.