Why isn’t my ipad syncing with my iphone for messages

Evidently your iPad is currently using a different AppleID account for iMessage. Until you are using the same AppleID account for both Messages and iCloud services, you may experience difficulties with synchronising Messages via iCloud. This should be relatively easy to correct...

On your iPad:

Settings > Messages > Send & Receive > AppleID

Beneath the section entitled "Start Conversations From" you will see in small blue text the AppleID that is currently being used for iMessage. Tap the blue text - and from the menu, select Sign Out.

Now shut-down and restart your iPad.

Settings > General > Shut Down

After restarting your iPad, return to your Messages settings - and sign-in to Messages with the same AppleID as is being used for iCloud.

Next, on your iPhone, verify that you have enabled Text Message Forwarding:

Settings > Messages > Text Message Forwarding - set to ON - and explicitly enable your iPad from the list of devices.

Finally, on both your iPhone and iPad, also ensure that Messages in iCloud is enabled:

Settings > [Your Name / AppleID] > Messages - set to ON

What do you mean it comes up with iCloud not the same on each device? If you logged in using a different AppleID then it isn’t going to be using the same iCloud. If you are signed in to the same AppleID on each device than you need to make sure you have the setting turned on to forward the messages to your iPad.

To do this on your iPhone go to Setting > Messages > Text Message Forwarding once in there, you can turn on the devices that you want to forward the messages to by selecting the slider and sliding the switch.

You might want to double check that it is signed into the same AppleID as your iPhone. If it is the same, I would suggest removing it from the account by logging out and then logging back in.