It depends on how much of a delegator the President is. They can get involved in everything, and run themselves ragged, or they can delegate to people they trust, and free up some time.
However, it is a 24 hour a day job, and they are always on call for emergencies, and when they have a moment to think, they have to figure out what their next priorities are.
There is constant reading to do. They are inundated with information to help them make decisions. There are constant discussions with all kinds of leaders.
I’m sure the President’s inbox is never empty, and is always overflowing.