How do I sync my iPhone with my iPad?

I don't believe that you CAN 'sync' between an iPad and an iPhone.

Both are designed to sync (and back-up) to a computer, either a desktop (i.e. Mac Mini or iMac) or a laptop.

There are also a lot of elements on each iOS device that you can sync to Apple's online iCloud service, such as Email accounts, Contacts, Notes… see Settings/iCloud.

And if you have both the iPad and iPhone configured to sync to the same iCloud account, then they will always stay 'in sync' with each other. Changes to you Calendar made not your iPad, for example, will automatically show up in the Calendar on your iPhone (as well as online on the iCloud web site.)

I hope this helps.

What is it that you are trying to do? You cannot sync the two devices together, but you can sync certain information between the two.