Presidential appointees are high-ranking employees of the federal government who are selected by the president. The president has free rein for some of these appointments; others require Senate confirmation.

The Constitution splits responsibility for filling top executive branch positions between the President and the Senate. The appointments clause (Article II, Section 2) says:

[The President] shall nominate, and by and with the Advice and Consent of the Senate, 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.

Presidents appoint the leaders of government agencies (often the people with titles such as director, secretary, chair, or administrator), oversight commission members (who review and supervise federal agencies to prevent fraud, and ethical lapses, among other things), ambassadors, and federal judges. You can see the full list of presidential appointees here.

The presidential appointment process has three steps:

1. The president selects and vets a candidate, then submits the nomination to the Senate.
2. The Senate reviews and votes on the nomination, usually in a committee.
3. The confirmed nominee is commissioned, sworn in, and assumes the full duties of the office.