Having all of your iMessage conversations sync across your iPhone and iPad automatically allows for a seamless experience when frequently switching between devices.
Although we have previously, and briefly touched on how to sync all of your iMessages between iOS devices, this is one question that keeps coming up. So, let's take a deeper look at how to ensure your messages will be synced.
Let's start with making sure everything is set up properly on your iPhone, before we move on to the iPad.
To begin, open the Settings app on your iPhone and then select Messages from the list of options. Toward the bottom of the screen you will see Receive At; tap on it.
If you don't already have an e-mail address registered with iMessage, you will need to to register an e-mail address now. After you have added an address, or if you already had one registered, you should see both your phone number and e-mail address listed. Below this section, you will see a Caller ID section. Tap on Caller ID to put the most crucial piece of this puzzle in place.
Make sure to set your e-mail address as your Caller ID. Doing so will allow you to send and receive iMessages from your e-mail address, instead of your phone number. You will still receive an iMessage sent to your phone number, but when you reply it will be sent from your e-mail address.
Now that we have iMessage set up on the iPhone with the Caller ID set as an e-mail address, we need to set up iMessage on our iPad with that same e-mail address.
On your iPad, launch the Settings app and select Messages from the list. You should see an e-mail address listed to receive messages, if this is the same e-mail address you have set up on your iPhone as your iMessage Caller ID, you are done.
If the e-mail address is different, you will need to add the same e-mail address you added on your iPhone and then set that as the Caller ID, the same way we did on the iPhone.
That's all there is to it. Going forward, your iMessage conversations should sync between your iPad and iPhone (or iPod Touch) almost instantly, assuming they are both connected to some sort of cellular or Wi-Fi network.