The best way to get around Munich is perhaps on two wheels as the city is exceedingly bike-friendly. Alternatively, a well-connected subway system not only makes it both easy to get around the city and venture out to the countryside nearby.
A rental car is a bit overkill in a city as bike-friendly and subway-heavy as Munich. Parking places are scarce in the city, but a car hire may be a good idea to reach more remote destinations outside the city.
Munich is truly a bike city with elevated and smoothly paved lanes well outside the flow of traffic. The city itself is also a manageable size, so it doesn't take long to get from point A to point B. Look for an affordable bike rental, which you will likely find by calling Call a bike from stations throughout the city. Just be careful during the icy winters.
Munich has the highest concentration of subway stops in any German metropolis, which means that the entire city is well connected to public transportation and nowhere too far from a subway stop. A week-long IsarCard is the most cost-saving option.
There are bus stops throughout the city, although the subway provides sufficient connections to the main sights. After the trains have stopped running, however, look for the night bus stops, marked by a winking owl. To be safe, you may want to confirm the timetables before heading out into the wee hours.
Taxis are available throughout the city, and Uber drivers are as plentiful ever. Taxi companies are regulated across the board by a central government agency, which means it's best to call the Taxizentrale at +498921610.