Yes, you can help a friend file on TurboTax.  Also the TurboTax Invite a Friend Program will also give you a $10 Gift Card for every new TurboTax customer who files their taxes — *up to $500 total.

But understand ---if you are using a paid version of online TurboTax, you get one return per fee.  If you use the same account and user ID for a second return, the first one is overwritten and lost forever.  Each return must have its own account and user ID.  And that may mean paying twice unless your friend can use Free Edition or Free File.

If you qualify to use it, there is another full-featured free version of the software:

Try Free File: 

You qualify if your income was $36,000 or less, or $69,000 or less if active duty military, or if you qualify for Earned Income Credit

https://ttlc.intuit.com/questions/1900583-what-is-turbotax-free-file-program

• https://ttlc.intuit.com/questions/2026912-how-do-i-switch-to-turbotax-free-file-program

If you switch to Free File you must create a new account and new user ID.