When you set up your Business Profile, that is where you can enter your EIN.
To set up your Business Profile type Schedule C in the Search at the top of the screen (you may see a magnifying glass there). There will be a popup that says Jump to Schedule C. Select that to get to the general area.
Follow through all the areas in the Business section of the TurboTax software and it will provide you with a lot of assistance. You'll notice blue links that have more information and details about the particular sections that will be extremely helpful. There you will find the field where you will be able to input EIN.
