Muggles are non Wizards or Witches. They hold no magical inheritance from their ancestry at all. Some people, think that Squibs are non-magical

Muggles hold normal jobs, such as teachers, and accountants, and farmers. Most magical people, hold jobs at the Ministry of Magic. They hold jobs such as, Hit-Wizards and Aurors.

Muggles dont know about the magical world, unless their children or sibling or someone in the family is a Muggle-Born. Before the International Statue of Wizarding Secrecy muggles would force witches and wizards to teach their children how to do magic.