“Impeachment is the process by which a legislative body formally levels charges against a high official of government. Impeachment does not necessarily mean removal from office; it is only a formal statement of charges, akin to an indictment in criminal law, and is thus only the first step towards removal. Once an individual is impeached, he or she must then face the possibility of conviction via legislative vote, which then entails the removal of the individual from office.
Because impeachment and conviction of officials involve an overturning of the normal constitutional procedures by which individuals achieve high office (election, ratification, or appointment) and because it generally requires a supermajority, they are usually reserved for those deemed to have committed serious abuses of their office. In the United States, for example, impeachment at the federal level is limited to those who may have committed “high crimes and misdemeanors”.
Impeachment has its origins in English law but fell out of use in the 18th century. It exists under constitutional law in many nations around the world, including Brazil, the Republic of Ireland, Philippines, Russia, South Korea and the United States.” https://en.wikipedia.org/wiki/Impeachment
“Has any president been impeached?
Only two presidents have ever been impeached by the House, and both were acquitted by the Senate. Andrew Johnson was targeted in 1868 because of a power struggle over policy in the post–Civil War South; Bill Clinton, in 1998, over his affair with White House intern Monica Lewinsky. Richard Nixon faced impeachment, but quit first. (See below.) Impeachment chatter is rife again following the appointment of a special counsel to investigate potential collusion between President Trump’s campaign and Russia, and Trump’s legal team has reportedly begun researching how to defend him if he’s impeached. The odds of Trump being impeached before the end of his first term have risen to 60 percent, according to betting house Paddy Power, and at least 26 Democrats and two Republicans have dropped the I-word. But the impeachment process is long, complicated, and heavily influenced by partisan considerations. If it happens, says Bill McCollum, a former Republican member of Congress who voted to impeach Clinton, “it’s not going to happen overnight.” https://theweek.com/articles/702650/how-does-impeachment-work