The impeachment process is basically his trial
The house first hears the articles, the witnesses and the evidence
If he is found guilty (like Clinton was ) then the Senate determines his consequences which can be removal. If you recall Since Clinton committed sexual crimes before he was in office and the statute of limitation would have run out the court ruled he could sued and would have to give written statements or appear before the parties involved. That’s iirc led him to perjury and loosing his law license But it was handled as a civil matter not criminal. Criminal they would have had to remove WJC from office before they could charge him with rape. Or murder or theft or .....
That does not mean Bill Clinton could have murdered someone on live TV and no one would have arrested him. The idea the Pres is the one American above the law is silly. On paper at least.