As head of the executive branch, the president must appoint the top officials for all of the federal agencies. These positions are listed in the Plum Book which outlines more than 7,000 appointive positions in the government.
1 When you have a Ph.D., sign your name either as Dr. Ernest Smith or Ernest Smith, Ph.D. 2  If you have a Ph.D. you should engrave all your personal envelopes or labels with either Dr. Ernest Smith or Ernest Smith, Ph.D.his is the teaching of St. Thomas Aquinas in his Treatise on Justice. (Question 58). Therefore, one should address a person with a doctorate by his title, and the person should have no fear in calling himself or herself by that name.
Never write both Dr. and Ph.D. before and after your name; nor should you use both designations when you write to another person who holds a doctorate - Dr. William Green, Ph.D. It is a redundancy. If you have a close relationship or are on a first name basis with someone who holds a doctorate, then on the envelope use his formal official title, Dr. William Green, and in the letter you may start with Dear Bill.