This technique allows the user to transfer chakra to another person. It is used by many users, each one of them has shown to use technique in different ways. Certain people, such as Minato Namikaze and Naruto Uzumaki could also mould the transferred chakra in order to adapt it to another person's specific chakra type. In the latter's case, due to Kurama's chakra, it also enveloped the recipients in a chakra cloak similar to his "Version 1" form, albeit with no tails. Later shown, he can create a tail from the cloak remotely.
The tailed beasts are also able to freely share their chakra with whomever they choose, and as Kurama has noted, it is a less complicated process for them than it is for humans.
In the anime, The Magaki Group uses this technique in a different way. First Nangō sends his chakra to Benten and Chūshin, and then both of them send it along with its own to Akaboshi, greatly enhancing the power of his techniques.