iMessage

iMessage is a secure messaging service that you can use to send and receive messages on your Mac, Apple Watch, iOS device or iPadOS device.

If someone sends a message to your email address or phone number using iMessage, you receive the message on all your Apple devices that are set up to receive messages sent to that email address or phone number. When you view an iMessage conversation, you see all messages sent from any device, so you can keep in touch with your friends wherever you are. See the Apple Support article Use Continuity to connect your Mac, iPhone, iPad, iPod touch and Apple Watch.

You need an Apple ID to use iMessage. If you’ve made purchases from the iTunes Store or App Store, or you’ve signed in to iCloud, you have an Apple ID.