Trump was impeached for breaking the law on military funds for other nations, passed by Congress and signed by a president.
Under the Law all military aid passed that Congress initiated, has to be distributed to the foreign nation by the executive, within 3 months of the bill passing. If the president can not do so in that time period, under the law, he must notify Congress that the president can't do that....
Trump HID that he was not distributing the congressionally passed military aid within the three months and failed to notify congress....
He hid it, Because He was illegally holding the military aid back until president ,Zelensky made an announcement on CNN international, that he opened an investigation in to Hunter and Joe biden, Trump's political opponent..... Trump said that he did not care if Zelensky opened an investigation or not in to the Bidens, he only cared that Zelensky would just SAY that he was....so Trump and Giuliani could use it, politically against his opponent.
Trump used our diplomats to try to do this for him, and Giuliani his campaign lawyer. The one diplomat who refused to use her position to illegally be involved in Trump's political campaign run, trump fired.
ALL OF THAT WAS AN ABUSE OF POWER AND ILLEGAL.