Text messages

Open "Settings > Messages > Send & Receive" on your iPhone and look at the Apple ID's listed there.

Then, open "Settings > Messages > Send & Receive" on your iPad and make sure that the Apple ID email address that is listed on the iPhone is also listed on the iPad. If not, add it and your iPad will begin receiving iMessages as well.

In addition to Tim Snoots' recommendations, you also need to check Settings > Messages > Text Message Forwarding on your iPhone to make sure your iPad is included there.

Good. Enjoy your Apple gear.