TurboTax Online is only good for one return. You would have to create
a new login, but you can use the same email address with a different
username. Tip: 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. https://ttlc.intuit.com/replies/3302087
https://ttlc.intuit.com/replies/3288574
