Impeachment can happen when a president is charged of "treason, bribery, or other high crimes and misdemeanors," according to the US constitution. The president can only be removed from office if convicted of the alleged offense. The process usually begins when a member of the House brings forth articles of impeachment. The House then votes on the charge, needing a majority to determine the ruling. Since Republicans have majority in both the House and Senate, it's unlikely Trump will be impeached. Removing a president from office is a two-step process.