The Constitution gives Congress the authority to impeach and remove “The President, Vice President, and all civil officers of the United States,” upon a determination that such officers have engaged in treason, bribery, or other high crimes and misdemeanors.
There are currently incriminating issues to be evaluated which have lead the U.S. House of Representatives to vote for impeachment. The House has held hearings and now is holding public events which will allow Republicans to call witnesses in the president’s defense. A trial by the U.S. Senate can conclude proceedings.
This legalese is the foundation of what we do in America. Guilty or not guilty will be the outcome. So yes, there are reasons for these actions.