the biographical sketch is written about someone else, it is mainly for the purpose of informing an audience about that person’s life. These types of biographical sketches usually provide a very detailed account of a person’s life and will include such information as the person’s full name, occupation and their life’s activities.
Biographical sketch can vary depending on who it is being written for and about 
If you are considering writing one for yourself perhaps you need a biographical sketch for a book or maybe you are making a presentation and it was requested that you provide a biographical sketch to be included in a program a biography tells the story of person's character,life,achivements