Message allows users to send texts, documents, photos, videos, contact information, and group messages over Wi-Fi, 4G or 3G
Imessenger is message application free text or chat if both device use imessenger.
you will have design and style of OS 11 and feature of OS 11.
Feature iMessenger for ios 11:
Free message or chat
Send message for group
Send photo via chat message
Edit or delete message from app
3D touch support in message
Protected your message (all message is encode, nobody read your message not save on cloud)
auto detected your friend have app imessenger via wifi and free sms
Sticker emoji send support
camera in message
Quick reply message on screen mobile
If you aren't sure whether you're using iMessenger or SMS/MMS texts, learn the difference. Depending on your carrier, messaging rates might apply when you send SMS/MMS. If you use i Message and Wi-Fi is unavailable, cellular data rates might apply.
3D touch support on imessenger
With Tapback, you can quickly reply to i messages with expressions, like a thumbs up or a heart. To reply to a message with a Tapback, follow these steps:
1 Open a conversation in Messages.
2 Double-tap the message bubble or photo that you want to respond to.
3 Select the Tapback that you want to send.