There are some kind of nails on its sole of soccer shoes. what is the function of them?

The nail-looking materials under the soles of a pair of soccer shoes are called, cleats. Cleats are also known as studs. These materials protruding underneath soccer shoes serve great purpose in preventing players to slip from soft or slippery surfaces. In the early days of soccer, cleats were made of metal, but through various innovations, materials can now range from aluminum, plastic, or rubber-made cleats.

This added material under the soles provides protection to players and is an invention that is very useful in the game of soccer. Brands like Nike, Adidas, and Puma are famous for making these kinds of football shoes.