How does ipad set up synchronous iphone SMS?

It is recommended to check the settings-information-sending and receiving first to ensure that the "How to contact you through iMessage" check box of all devices is consistent. Under normal circumstances, after new information comes in, as long as it is read on one device, there will be no reminder on the other device, but the content can be synchronized. (Only iMessage can be synchronized, not ordinary SMS). I hope I can help you.