Follow these steps if you want iMessage like experience for your Android “Messages” App.

Prequisites :

Steps:

  1. Turn off WiFi.
  2. Open the Activity Launcher app.
  3. Tap the dropdown up top and switch from “recent activities” to “all activities.”
  4. Scroll down to find “Messages.”
  5. Tap on it and find the “Set RCS Flags” activity. Select it to open the hidden RCS configuration settings in Google Messages.
  6. Select the dropdown under “ACS Url” and select the ‘http://rcs-acs-prod-us.sandbox.google.com/’ option.
  7. Go home and clear Messages from your recent apps list. Open it back up and you should see a message at the bottom asking you to set up Chat. Accept it by tapping on “upgrade now.”
  8. After starting setup, re-enable WiFi and wait a few minutes. If successful, go to Settings > Chat features and it should say “Status: Connected” up top.

Troubleshooting :

If that didn’t work for you, then try these additional steps:

  1. Go to Settings > Apps and find “Carrier Services.” It’s a system app, so you’ll need to tap on the overflow menu and select “show system apps.” Once you find it, clear data on the app.
  2. In Settings > Apps, find Messages and force stop it.
  3. Repeat steps #1-6 from above, but while you’re in the RCS configuration settings, expand the OTP Pattern dropdown and select ‘Your\sMessenger\sverification\scode\sis\sG-(\d{6}).’

Source : XDA Developer

Skip the wait: Enable RCS right now in Google Messages for any carrier

Note : Please, follow this steps with your care. It worked for us , might not work for all.