The tradition of peaceful presidential transitions is a hallmark of American democracy. One administration hands power to the incoming administration. This transition is largely ceremonial, but there are also formal procedures the president-elect goes through.
Because president Obama’s term is coming to an end and his successor has been elected, he is considered a “lame duck” president. A lame duck president may hold less sway with other politicians because his term is ending, but he can also issue more controversial executive orders with less chance of personal consequences. This can benefit the president if he has an agreeable Congress.
President-elect Trump will attend hundreds if not thousands of meetings and briefings in the time before his inauguration. He will be informed of the details of his duties and will be briefed on the classified information that presidents must be aware of. These briefings are not technically mandatory, so the president-elect must plan them around his schedule. Aside from intelligence meetings, the president-elect must meet and choose his cabinet members. If the president-elect, his running mate, or his cabinet members hold a public, they must resign at any time before inauguration day to ensure smooth transitions of power.
When the incoming president is sworn in, he officially becomes the president of the United States, and all of his predecessor’s powers are entrusted to him.