Read receipts are an optional feature to see and share when messages have been read.
How do I manage read receipts?
Signal Settings > Privacy > Read Receipts
Both you and your contact must have it enabled to see this status.
What happens for disappearing messages?
The disappearing message timer starts after the message is sent. After the message has disappeared, you cannot see the delivered or read status.
Learn more about message details (timestamps), delivery indicators and disappearing messages.