Standard fields are default fields built-in to Salesforce. They can not be deleted. On the other hand, several aspects of standard fields can be customized as follows:
- Edit, delete, or add values in picklist fields and set a default value
- Rename the field label
- Add a help text for the field
- Set dependencies between fields
- Configure validation rules
- Make a field required via a validation rule or via the page layout
- Set field history tracking to track changes including the date, time, nature of the change and who made the change
- Control the display of fields in page layout (possibility to hide them)
Set field-level security to control access to fields
When you change the label, the new name appears on all pages the user sees. However, Salesforce online Help and Setup pages always display the original names for standard fields.
The API name of the standard fields can not be modified.