What?

The president serves as both the leader and a figurehead for the nation. He/she is responsible for foreign diplomcay and running the nation. The President appoints a Cabinet who serves as trusted advisors throughout the Presidency. The Vice President also serves in assisting the President in various functions.

How?

The president gets his/her power from Article 2 of the United States Constitution. The Constitution provides guidlines for electing a President and the powers of the President

The powers of the President can be divided into 2 different categories: expressed and implied.
Expressed Powers = Powers explicitly given by the Constitution
Implied Powers = Powers not expressed in the Constitution but the President still has them