Currently, only Import Types of Employee support the ability to import data in a non-standard format. A non-standard format is a format that is different from the Standard Import Format that is defined on the Data, Imports, Standard screen under the Layouts menu.
For Import Types of Employee, it is possible to specify which fields will be included in an Import File by using the Field Mappings Tab of the Custom Import. This can be useful when importing only a subset of employee data.
Example: For example, a Custom Import of Type Employee can be used to only import (or update) email addresses in the system using two columns of data in a Microsoft Excel File (Column A = Employee ID, Column B = Email Address). By creating a Custom Import with only these two columns mapped on the Field Mappings Tab, this Custom Import can then be referenced from the Data > Imports > Standard screen by selecting "Custom Import" as the Import Type and then selecting the desired Custom Import.