What are the three powers of Presidency?

Answer

There are considerably more than three.

US Constitution, Article I, Section 7

"Every bill which shall have passed the House of Representatives and the Senate shall, before it becomes a law, be presented to the President of the United States. If he approve, he shall sign it, but if not he shall return it with his objections to that house in which it shall have originated - - If two thirs of the House [and of the other house] shall [again] agree to pass the bill, it shall become a law - -. If any bill shall not be returned by the President within ten days (Sundays excepted) after it shall have been presented to him, the same shall become a law in like manner as if he had signed it, unless the Congress by their adjournment prevent its return, in which case it shall not ba a law."

Article II, Section 2. The President

"shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual service of the United States

he may require the opinion, in writing, of the principal officer in each of the Executive Departments, upon any subject relating to the duties of their respective offices.

he shall have the power to grant reprieves and pardons for offences against the United States, except in cases of imperachment

He shall have power, by the advice and consent of the Senate, to maake treaties, providing two-thirds of the Senate concur

wit the advice and consent of the Senate, he shall appoint Ambassadors, other public ministers and Consuls, Judges of the Supreme Court, and all other officers of the United States whose appointments are not herein otherwise provided for, and which shall be established by law - -

[he] shall have power to fill all vacancies which may happen during the recess of the Senate, by granting commissions which shall expire at the end of their next session.

Sec 3, He - - may on extraordinary occasions, convene both Houses [of Congress] or either of them, and in case of disagreement between them with respect to the time of adjournment, he may adjourn them to such time as he may think proper."