The content of labels is controlled in the Label with drop-down list in the Layer Properties dialog box. You can label an object with any column from its associated table. For example, you can label the STATES table with the state name, abbreviation, 1990 population, or any other field in the STATES table. Simply choose a column from the list, and the objects in that layer will be labeled with the information contained in that column.
Note: The Layer Properties dialog box only lets you set a label with expression on one layer at a time. After selecting multiple layers in the Layer list, the Label with list Layer Properties dialog box disables and shows a message that says Mixed.