I looked up your answer online and so far this is what I've researched.
The number of federal officials impeached by the House of Representatives includes two presidents. The 2 president's were Andrew Johnson and Bill Clinton. Both of them were later acquitted by the senate.
Here's the link to it so you know where to find it: https://www.google.com/search?q=Who+has+the+power+to+impeach+the+president%3F&sa=X&ved=2ahUKEwjbjZ7MgrHeAhVFG6wKHUGzB0MQzmd6BAgKEAk&biw=952&bih=460
I hoped this helped!