What should an administrator use as an identifier when importing and updating records from a separate financial system?

An External ID is a custom field that contains unique record identifiers from a system outside of Salesforce. It allows Data Loader and other integration tools to match records in Salesforce with records from the external system during import and update operations, preventing duplicates and ensuring data consistency.

The Record ID is Salesforce's internal 15 or 18-character unique identifier for records, which is generated by Salesforce and not suitable for identifying records originating from an external system.

A Rich Text field is used to store formatted text and cannot be designated as a unique identifier for matching records during data operations.

An Auto-Number field automatically generates a sequential number for new records within Salesforce and is not designed to store and match identifiers from an external system.