According to 2017 NEC, the laundry room needs its own 20-amp circuit, and can be used to operate both a washing machine and dryer. If you have an electric dryer, however, it MUST be on its own 240V circuit. The most common is a 30-amp circuit, but the size of the breaker is specified on the appliance’s label.
Most dryers on the market today are rated 30-amps. Standard size electric dryers need 220V of electricity to dry your clothes. You can always tell the voltage of your dryer by the type of plug.
Washing machines should be connected to a 20-amp circuit breaker, and wired with a 3-wire, 12-gauge cable. Electric dryers should be wired with a 4-wire, 10-gauge cable (three conducting wires and one ground wire).