I am self employed. How do I take advantage of the 20% pass-through deduction in 2018? Do I need to set up an LLC? Can I still use Turbotax self employed software?

Does an LLC qualify for the 20% deduction?  Is there a maximum income limit for a professional to get this deduction (dentist)?  If there is a max. income limit, is the income gross income of net income after expenses and deductions?  Can I use Turbotax online self employed version or another version to file my taxes after I set up LLC?