An invention is the creation of a new material or we can say that the action of inventing something new is called invention.
Today we live in the age of science.But in past we don't have enough knowledge or we can say information. We have to travel a long distance by foot . Then we "the great human beings" invent the rotating wheel which in later we use it as a roller then sledge then sledge on roller and so on . See in the first figure .
In the ancient time or past we had very problems in the farm lands says food take so much time to grow , ploughing etc . But because of these machines ( Tractor ) we can easily plough and the food gets ready in shorter period of time . Also these machines are used everywhere . We use air conditioners to keep our room cool , we use room heaters to keep our room hot . We use vehicles to travel long distances.See in the second image.
Telephones are also a great invention of the men . We can communicate with our relatives or friends who are living far away from us . These telephones also play a crucial role in the business . We can save our time without travel a long distances with the help of mobiles/telephones . See in the third image .
Also computers have a great importance in the modern society. From the beginning to the modern world computers are progressing. This computer is not a simple machine . Computers change the lifestyle of the people . Only through computers our country is a developed and success country.
These all inventions have their its own merits . All are best inventions . So we can't say that only one is the best invention as every invention play a crucial role in our life .