Let others know you’ve read their text messages
You can send read receipts so that people you have a conversation with know when you’ve read their messages.
You can send read receipts for all conversations you have using an account, or for just one conversation. If you turn on read receipts for an account, you can still turn them off for a single conversation—and vice versa.
Send read receipts for one conversation
Select a conversation, then click Details in the top-right corner.
Select Send Read Receipts.
Send read receipts for all conversations
Choose Messages > Preferences, then click Accounts.
Select the account, then select “Send read receipts.”