Thank you for taking the time to get in touch with our Customer Support Team. We know that it would be more convenient and can save you time to add a new EIN in your account without calling us.
However, for now, we need to contact them again to add EIN to your subscription since we no longer have this option in QuickBooks 2020. We want to ensure your account will not be exposed to the other users.
Please check this article to see the available time you can contact our QuickBooks Support Team: Support hours and types.
Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.