The instructions/info online is incorrect. I see nothing allowing me to change my username (which is AN OLD JOINT EMAIL ADDRESS) to my CORRECT username (which I plan to use). I COULD sign in, but the OLD email address sends email to BOTH me and my ex (who I'm not interested in sharing anything with!) Not certain if they actually sent anything to her when I signed in or not, but the USERNAME NEEDS TO BE CHANGED!
As long as you can sign in, you can change your Email address.
Follow these steps to change your Intuit Account credentials directly in the Intuit Account Manager:
Important: Your Intuit Account is connected to all of your Intuit products. Any changes you make apply to all of your Intuit products, including QuickBooks, TurboTax, Credit Karma, and our professional tax products.