An example: one letter with several meaningful dates
An incoming letter might be received on Monday, assigned on Tuesday and answered on Thursday. The outgoing reply may then have its own preparation, approval and delivery events. Keeping the dates separate helps explain both operational progress and the next action. A single timestamp cannot describe every stage of the exchange.
For your own workflow, list the statuses people need to act on rather than every possible technical event. Identify which are confirmed by a person, which come from a provider and which require follow-up. A queue of items waiting for review answers a different question from a list of carrier events. Discuss the views that each role needs, including how an exception should appear and who should investigate it. Keep the underlying document and its references available to authorised reviewers.
Postal progress and email progress are separate
Sending one letter by post and email creates two delivery journeys. An email service may accept a message without confirming that anyone opened it. A postal order can be paid for and printed before it is handed to a carrier, and carrier handover does not necessarily mean final delivery. Epistles should show these stages separately and record the source of each status.
The customer should be able to understand what is completed, what is still pending and what needs attention. If an email bounces but the postal letter is dispatched, the correspondence record should show both facts, not one misleading green tick. This level of clarity helps people decide whether to follow up, correct an address or retain supporting evidence.