iMessage is a secure instant messaging service developed by Apple that allows users to send and receive text messages, photos, videos, documents, and more through the Messages app on Apple devices such as iPhone, iPad, Mac, Apple Watch, and Apple Vision Pro

. It works over the internet using Wi-Fi or cellular data, so messages sent via iMessage do not count against your SMS or MMS cellular messaging plan, though data charges may apply

. Key features of iMessage include:

• End-to-end encryption, ensuring only the sender and recipient can read the messages

• Messages appear in blue bubbles when sent via iMessage, while SMS/MMS messages appear in green bubbles

• Ability to see when the other person is typing and read receipts if enabled

• Support for rich media like high-resolution photos, videos, stickers, Memoji, audio messages, and message effects

• Collaboration tools, message editing, unsending, scheduling, and group conversation management

• Integration across Apple devices so conversations sync and can be continued on any device signed in with the same Apple ID

To use iMessage, you need an Apple ID and an Apple device. Messages sent to non-Apple devices automatically fall back to SMS/MMS

. In summary, iMessage is Apple's proprietary messaging platform that enhances texting on Apple devices with advanced features, security, and seamless device integration, distinguishing it from standard SMS texting