About Assigning a Field Type
When creating a custom field, you must assign a field type.
The field type determines required input. Although some steps in the wizard are required for all field types, additional steps may be required for specific types. For example, if you add a text field, and you do not use a pre-defined type, you must identify the maximum number of characters allowed for the new field.
The wizard may also provide additional, non-required options that allow you to further define how the field appears. For example, when adding a text field, you can specify that the field is a textbox, combo box (drop-down list), URL link, or notes field.