Three forces act in the micro cosmos. They act directly between quarks and leptons at this level. Since the word "force" sometimes gives a misleading picture, one instead uses the word "interaction". The Standard Model describes the different interactions with the help of force carrying particles. The three types of interaction are:

There is a fourth type of interaction that is not a part of the Standard Model: gravity. It is supposed to be mediated by the graviton (not yet discovered). The gravity between single particles is so weak that it is negligible in micro cosmos.