add a return for son

[angelatrigona]

Can I file my son's return using my user ID with turbo tax?

[DoninGA]

No.  You have to create a new account with a new User ID and a new email address if you are using the TurboTax online editions. 

Go to this website and click on Sign up to start a new account - https://turbotax.intuit.com/personal-taxes/online/file-your-own-taxes/

[MinhT1]

No.

If you are using TurboTax Online, you cannot prepare and file a tax return for another person using an existing TurboTax account. You'll need to create a new account, distinct from the account you used to file the first return.

If you are using TurboTax Desktop, you can start a new return by clicking on Start a new return on the Welcome page of TurboTax.

Please read this TurboTax Help topic on how to start a new tax return for another person.