How do I transfer contacts from my iPad and iPad mini 3 to iPhone 6 ?

Hello there, sarafromsilverthorne.

One great way to transfer contacts effortlessly, would be to use iCloud Contacts. The following Knowledge Base article provides how to do just that:

Get help using iCloud Contacts - Apple Support

You will want to follow these instructions first on your iPad, and then also turn on the feature on your iPhone:

Turn on Contacts and update your device

• Tap Settings > iCloud on your iPhone, iPad, or iPod touch and make sure that Contacts is on.
• Install the latest version of iOS that's supported by your device.

Thanks for reaching out to Apple Support Communities.

Cheers.