User-defined non-inherited fields can be deleted from a table in ServiceNow. These are fields that are created by users on a specific table and are not inherited from a parent table. Inherited fields cannot be deleted from a table, as they are defined on a parent table and shared by all child tables. Any field on a table cannot be deleted, as some fields are system-defined and essential for the table functionality. Table records are not deleted when a field is deleted, as the field deletion only affects the table structure and not the data. Reference: Delete fields