Their are two variations of transmission in vehicles, manual and automatic. Automatic transmission is taking over manual transmission since it was first introduced in 1940 by General Motors Cadillac.
Still nowadays, several people prefer to drive manual cars over automatic cars. Well, it is their own preference. But in this video, you will find out the difference between manual and automatic tranmission.
This video shows analysis of both the transmissions and differences in detail which can be understood easily.