Members of The Church of Jesus Christ of Latter-day Saints have a specific way in which we address one other. We call each other by the title of brother or sister, respectively, as well as other titles for those who have a specific calling such as that of bishop, president, prophet, and apostle.
Brothers and Sisters:
When addressing other members of the Church of Jesus Christ we commonly use the title of brother or sister respectively, along with the individual's last name. This comes from the belief that we are all spirit sons and daughters of God, who is our Heavenly Father. We consider everyone to be our brother or sister. For example: If I see Wendy Smith, I would address her as Sister Smith.
Members who currently hold callings as a president in a presidency are addressed as President. These leaders preside over a specific area or organization. Continuing to address a leader as president when they no longer hold such a calling is not necessary. Some callings that use the title of president are: Stake President, Mission President, Temple President, Relief Society President, and Branch President. Each member of The First Presidency (see "Organization of the LDS Church"), and the President of the Quorum of Twelve Apostles use the title of president.
The Bishop of a local ward should be addressed with the title of Bishop. For Example: A local ward's Bishop, Ted Johnson, would be called Bishop Johnson by members of the LDS Church.
Men who serve missions are called by the title, Elder, during the time of their service. When they are no longer full time missionaries they are no longer called by that title. LDS Church leaders who serve in the Quorum of Twelve Apostles, Seventies, and Area Presidencies, are also addressed by the title of Elder. Women who serve missions are addressed by the title of sister. For example: Marge and Edward Anderson (a couple serving a mission later in life) would be addressed as Sister and Elder Anderson.
LDS Church Callings:
See the article, "LDS Church Callings," to learn how members receive positions within the LDS Church.