You can use the same email
address if you choose however, you would need to create a new login for the
second tax return. Up to 5 accounts can be tied to the same email address.
If you're preparing multiple returns for family members, it's more economical to switch to the TurboTax CD/Download software, which lets you e-file up to 5 federal returns at no additional cost. More info
Please follow the steps in
the FAQ for instructions on starting another return
in TurboTax
Online.
https://ttlc.intuit.com/replies/3288574
