That is false info - if you are a citizen your SSN is your tax ID and anyone paying you can send you a 1099 for you to file with your personal taxes. You only need an EIN if you are going to be hiring employees.
You do not need to do anything to be a sole proprietor otherwise. The main reason for setting up an LLC is liabilities. In the event you were to be personally sued for something (unlikely in the designer space) then your LLC can hold the assets vs you being at risk yourself.
In a decade of freelancing here in NY I only pay $250-300 for my personal, wifes, and freelance taxes.