Custom fields may be configured for entering information specific to your company, and can be configured to always appear or appear when a certain category is selected. You may be required to enter information in custom fields, and if a work item is recategorized, data saved in custom fields is retained and the custom fields associated with the newly-selected category set are added.
You can use custom fields to facilitate the recording of information such as:
For incidents: preferred method of contact
For changes: back-out plans, procedures, tests, and affected systems and services
For problems: closure codes, date and time of root cause analysis activities and results and resolution recommendations
For knowledge entries: external source