Some people show their family history using a family tree. A family tree is a diagram of the members of a family. With a family tree you use lines to show how people are related, for example, people who are married or have children.
Some people keep track of their family history data in a genealogy database on their computer. Examples of data that a person would save are dates and places of births, marriages, and deaths. Other information that might be saved are records of military service, census records which show where ancestors lived at a certain time, immigration data, education, occupations, and even photos of the ancestors. The person building the database can usually decide to save many kinds data—news articles, stories that were told in the family (oral history), information on religious ceremonies, wills or inheritances, information from family letters, customs, or how world or local events affected the family. The advantages of using a genealogy database are that it helps to keep the data organized, especially when relationships change; it can generate several types of charts or tables with the data filled in; it may make it easier to share data with others; and it takes up less room than paper and notebooks.
People study genealogy (family history) for many reasons. They may want to help someone be reunited with their family after war, natural disasters, foster care, or adoption, or find living relatives. They may want to learn about their ancestors (parents, grandparents, great-grandparents, etc.) from hundreds of years ago. They may want to track hereditary diseases that may be passed from parents to their children. (This would overlap with the study of genetics.)
Some people used to (and some still do) study genealogy to keep track of wealth, land and power because people used to argue that it belongs to their family. These people use genealogy to help it stay in the family and prevent untruthful claims to the wealth, land or power.