Google Messages latest update is all about fighting spam
A support document that contains instructions on how users can report spam in a group message is now live on the app's support page, AndroidPolice reports. Keep in mind though that if you're using Google Messages and don't see the new option yet, you should wait a few more days since the update is rolled out in waves.
When you report spam in a group message, the spammer is reported and the message is sent directly to your “Archived” folder, Google explains. To report someone, simply open the Messages app, then the conversation you want to report, tap More Group details, and then choose Tap Report spam.
Don't try to download anything from the Google Play Store since this seems to be a server-side update. You'll just have to pray that the new feature will appear on your phone sooner rather than later.