In most cars where voice recognition is fitted, there is a button on the steering wheel which activates the voice control system and allows the driver to speak commands instead of using the infotainment system. It can be used to control features such as the satellite navigation, radio and media or phone (through the cars Bluetooth connection). In some cars there will be specific phrases displayed for you to use depending on what you want to do, for example starting with navigation, followed by enter destination and so on. The voice control system will respond at each point to confirm it has understood correctly.
Some cars will learn the drivers voice over time and understand phrases and words that make it easier to use, while others are being developed to be able to respond to requests such as I want a coffee it will then give you your options as to where you will be able to find one nearby.
While some are more effective than others, voice recognition is being increasingly utilised in cars in order to boost convenience and safety for the driver less time will be spent fiddling with buttons or touchscreens, and instead both hands can be kept on the wheel and eyes kept on the road.
Where it isn't fitted and Apple CarPlay and Android Auto are, their respective voice command systems (such as Siri) can be used instead.