The answer is: A Certified Estate Planner and Certified Public Accountants.
In order to prepare an estate you would need the help of a Certified Estate Planner who might be a member of the National Institute of Certified Estate Planners (NICEP).
You would also need a Certified Public Accountant who is licensed to operate in your state. They will take care of all tax matters and ensure your submissions to the Internal Revenue Service (IRS) are managed properly and under the law.