If you haven't filed, registered or paid you can try to clear and start over
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-online/00/26444
To clear in the Mobile App
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-the-mobile-app/01/26808
Or you could just leave this account and start a new account. Online is only good for 1 return. But you can use the same email address for 5 accounts. How to start another return in the Online version
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-online/00/25596