Earlier this week, Apple rolled out iOS 18 Beta 2 with support for Rich Communication Services (in the US). The experience of using Google Messages to talk to someone with an iPhone over RCS is pretty straightforward, though it’s clearly the first take.
After updating to iOS 18 Beta 2, an “RCS Messaging” toggle (Settings > Apps > Messages) is enabled by default if you’re on a compatible carrier, like AT&T, T-Mobile, or Verizon. Right now, RCS on iOS cannot be enabled if you’re on an MVNO, like Google Fi. However, it does not matter what carrier the Android recipient is on once RCS is active on your iPhone.
In Google Messages, opening an iPhone conversation will reveal “RCS message” in the text field. Delivery/read receipts and typing indicators, as well as higher-resolution images and videos, just work.
Google Messages will mark that the conversation is not end-to-end encrypted…
Source 9to5google.com