Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version
Create a new account for yourself with a different user ID. An online account is only good for one tax return.
The TurboTax online editions can only be used to complete and file one tax return per account and User ID. If you want to start another tax return using the online editions you will need to create a new account with a new User ID - https://turbotax.intuit.com/personal-taxes/online/