The specific laws governing the operation of motor scooters on the street vary by state. In general, however, it is typically required to have a valid driver's license or instruction permit in order to operate a motor scooter on the street.
In some states, a separate endorsement or classification may be required to operate a motor scooter on the street. For example, in California, a person must have a valid driver's license or instruction permit and either a "M1" endorsement or a "M2" endorsement in order to operate a motor scooter on the street. An M1 endorsement allows a person to operate a motor scooter with a motor of 150cc or less, while an M2 endorsement allows a person to operate any motor scooter.
In other states, a motor scooter may be classified as a "moped" and may have different requirements for operation. For example, in Virginia, a person must have a valid driver's license or instruction permit and a "M" endorsement in order to operate a moped on the street. A moped is defined as a motor vehicle with pedals and a motor of 50cc or less.
It is important to check the specific laws and requirements in your state to determine what is needed to legally operate a motor scooter on the street.