Put simply, a fuel pump is an integral part of your vehicle's fuel system responsible for transferring the gasoline from the gas tank to the engine. This transfer of fuel allows the engine to be able to power up and run. In modern vehicles with internal combustion engines, there are two main types of fuel pumps: mechanical and electric. 

Fuel pumps have been around since the early days of automobiles. The first type of fuel pump was a mechanical fuel pump, which uses an internal spring-loaded diaphragm to pump gasoline from the tank to the engine. These were standard for many years but were eventually overtaken by electric fuel pumps in the 30s and 40s due to their ability to provide more efficient fuel delivery at a lower cost. 

Today, both electric and mechanical fuel pumps are still used in most cars and trucks, although the majority of vehicles now use electric fuel pumps due to their efficiency and economy.