Althought San francisco is such a small city, there are many forms of transportation to get around town.
Walking is definatly an option, but it can be overwhelming. so, Here are many options to get around town.
Municipal Transportation Agency also known as Muni is a form of public transportation that has lines the can take you end to end of San Francisco,
but the fequency of buses averages between 20 minutes to an hour based on the time of day and location.
If you plan to drive in town be sure to check out these web services that have most of the major parking lots in the city. This service is also available in moble app stores.
App Based Transportation
UBER and Lyft are the most popular app based transportation used in San Francisco. Flywheel is an App for TAXI and is $1 more than normal rates.
There plenty of cars available for these two companies so there will be very minimal wait time.
Here is more information about TAXI rates and services.
The best way to explore the city it is to rent something you can stop and go when you want like a bike, Segway, or even Gocar.
For more transportation coming in and out of San Francisco