Moped permit requirements vary from state to state. In general, however, you will need to be at least 16 years old and have a valid driver's license. You may also need to pass a written test and a driving test. Some states also require moped riders to wear helmets.
To find out the specific moped permit requirements in your state, visit the website of your state's Department of Motor Vehicles (DMV) or Department of Transportation (DOT).