MUNI runs both streetcars that operate on surface streets and underground, and buses that cover most of the city. After you pay the driver, he or she will hand you a printed ticket called a transfer. If you get off the bus and want to ride another bus or train you can give them your transfer so that you don't have to pay a second dollar. You can use a transfer once, and only within two hours of when you received it. In addition to the streetcars and busses MUNI runs the cable cars.
Cable cars are a way to travel around downtown to selected areas.
The Bay Area Rapid Transit System runs from Daly City to downtown San Francisco and the East Bay, including Oakland and Berkeley. There are no transfers.