How can I sync my iPhone and ipad?

What exactly are you attempting to do? Sync them in what way specifically. I'm going to guess you want to use Continuity Services, so see if this link helps you --> Use Continuity to connect your Mac, iPhone, iPad, iPod touch, and Apple Watch - Apple Support

If this isn't what you're looking for, perhaps this will help --> Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support