Impeachment is the process of removing the president from office. The House of Representatives proposes it, and the Senate has to agree/disagree with it.
The Senate becomes jury and judge, except in the case of presidential impeachment trials when the chief justice of the United States presides. The Constitution requires a two-thirds vote of the Senate to convict, and the penalty for an impeached official is removal from office. The Constitution gives the House of Representatives the sole power to impeach an official, and it makes the Senate the sole court for impeachment trials.