Why do you need a separate business account? Do you want to buy the separate Turbo Tax Business program under a different ID? Make sure you are logged out of your personal account and then buy the new program and set up a new account. You might need to use a different email address. You can buy the Business program here, https://turbotax.intuit.com/small-business-taxes/cd-download/
Do you need to file a separate Business return like a 1120 or 1065? Or are you a Single Member LLC, sole proprietor, independent contractor, self employed, etc.? Then you file it on schedule C in your personal return.
Otherwise call support to ask how.
How to contact Turbo Tax
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-contact-turbotax/00/26991
What is the Turbo Tax phone number
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632