The function `std::shuffle` is part of the C++ Standard Library, specifically included in the `<algorithm>` header. It randomly rearranges the elements in a given range, which can be useful for tasks like shuffling a deck of cards or randomizing a list of items. The function requires a random number generator to produce the randomness needed for shuffling. To use `std::shuffle`, you specify the beginning and end of the range you want to shuffle, along with a random number generator. This allows for flexibility, as you can use different generators to achieve various shuffling behaviors. The result is a new order of elements, enhancing randomness in your programs.