What are Sunnis Shiites and Wahhabi Muslims?

Shia Muslims believe in Imamat as one of five pillars of Islam. unlike Sunni Muslims. Wahhabis are a group mostly centered in Najd, Saudi Arabia and they believe they are the only Muslims in the earth and they call any non-wahhabi as infidel and enforce other Shia or Sunni Muslims to join them and believe in their interpretation of Islam.