How do I cancel and/or delete my account?

TurboTax accounts cannot be deleted.  See this TurboTax support FAQ - 

https://ttlc.intuit.com/community/using-turbotax/help/can-i-delete-my-tax-return-in-turbotax-online/01/25795

If you have not paid for the online edition you are using, have not filed your tax return or registered the Free edition, then you can clear your return.  Click on Tax Tools on the left side of the program screen while working on the 2018 online tax return.  Click on Clear & Start Over.

We can't delete your account, per se.  But you can remove the data.   We will keep the username and password you created in case you ever want to return to the website. 

If you would like to erase the data you have entered, you can do that by following these directions:

1. While in your TurboTax Online program (after clicking Continue your return)
   Select tools.
2. Then click onClear & start over.
3. On the Are you sure you want to clear your return? pop up screen, if you are sure about clearing all your entries and starting over, click 
4. Then a new screen confirms you have cleared your entries, click Continue.

All of your entries will now be erased.

If you cannot clear the account then you can simply let it go dormant.