An RCS message is a text message sent using the Rich Communication Services (RCS) protocol, which is a modern upgrade to traditional SMS and MMS messaging used on mobile phones. Unlike SMS, which is limited to plain text and 160 characters, RCS supports rich features such as:

• Sending high-resolution photos, videos, audio, and files without size limits
• Read receipts to know when messages are seen
• Typing indicators to see when the other person is typing
• Enhanced group chat management, including naming groups and managing participants
• Interactive elements like suggested replies and action buttons for tasks such as booking or payments
• End-to-end encryption for secure communication (especially between users on Google Messages with RCS enabled)
• Seamless integration with native messaging apps on Android and now also supported on Apple devices with iOS 18 and later

RCS messages are sent over the internet or mobile data rather than the traditional cellular network SMS system, allowing for richer, more interactive, and secure conversations directly within your phone's default messaging app without needing third-party apps

. It is designed to replace SMS/MMS by combining the simplicity of texting with the advanced features of modern chat apps like WhatsApp or iMessage, but natively integrated into the phone's messaging system