How do I help my 18 year old dependent son file his taxes when I have already completed mine?

[Rachel_W]

First, you will need to create a separate account for your son in TurboTax Online.  To do this, at the TurboTax login page, scroll down to Create New Account or click the signup screen link here:  https://myturbotax.intuit.com/sign-up/.

As you walk through the TurboTax interview process for your son, he should answer "YES" to the question "Someone else can claim me as a Dependent" and "YES" to "and this person will claim me on their 2018 Tax Return".