iMessages, Notes, Calendars, Safari browsing tabs, Photos, Videos, Email, Music/iTunes, etc.
Pretty much all of the Apple apps are interconnected.
With iOS 8, you can:
1. connect to your cellular connection on your iPhone automatically (with one tap).
2. Make and receive a call on your iPad.
3. Also SMS.
4. Continue working from your iPhone on your iPad (Apple apps).
Can you text with the ipad?