My last name is misspelled in the return form. It should read Martinez

Go to my account

click account settings

You will see your information, to the right of your name should be the edit link

or you can:

To amend your 2016 taxes if you need to make changes and your taxes were already e-filed and accepted (or mailed)
  1.Sign into your TurboTax account, if you're not already signed in.
  2.In the 2016 tax year section, click amend (change) return.
  3. In the pop-up, click amend using TurboTax online.
  4.Click continue on the we'll help you change (amend) your return screen.
  5.Follow the on-screen directions to amend your return.
  6.When you're done, will provide instructions to print and mail your amended return because and amended return can't be e-filed.