Last week, Google releases a new handy feature for Google Messages which enhances the user experience for example YouTube PiP. Now, Google is testing the newly delivered and read status and status indicators on Google Messages. Recently, Google is testing new features on the Google Messages like the Delivered indicators and Read receipts.
You can find these below your last mess below your last sent message between the sent time and lock icon for end-to-end encryption (E2EE).
Add Realmicentral to your Google News feed. 
This new feature of Google Messages is now in testing a system of checkmarks that has three indicator states that slightly differ between individual and group conversations.
In individual chats:
1 checkmark = Sent
2 checkmarks = Delivered
2 filled-in checkmarks = Read
In group chats:
1 checkmark = Sent
2 checkmarks = Delivered
“Seen by [x]” or “Read by all” = Read
After, seeing these it same as usually seen in the other chatting apps. If it were just the first two checkmarks, this would be a fairly standard approach to deliver/read in messaging apps. iMessage just uses text, and that is the better approach in our opinion.
Checkmarks are ubiquitous and might be more familiar to people, but being able to just read out Delivered and Read requires less translation, no matter how obvious the icons are. Although, the fact there’s a difference between two checkmarks and two filled-in checkmarks is an unnecessary complication.
Finally, as you know this feature testing running so, when it will widely roll out then only you use it on your device.