Fields are used to hold data of a specific type such as text strings, numeric values, date or time. Fields can also represent information as a true/false indicator using check boxes, or as option menus allowing you to select one of several pre-defined choices.
For some fields, you can also set constraints to further restrict data that can be entered in the field. For example, a text field can be restricted to alphabetic characters with no spaces allowed, or a date value can be forced to display as Month day, year no matter how it is entered.