If you bought the Desktop program and installed it you are done. Just ignore the email. It might be for an online account you have. Sounds like just advertising. I get them too for my test accounts. If you want to check
Contact Customer Service
5am-9pm Pacific Time
7 days a week
https://support.turbotax.intuit.com/contact/
What is the Turbo Tax phone number
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
