My iPhone 6 will not pair with iPad using Bluetooth

What exactly are you trying to do? There are things that you can do between an iPhone and iPad, such as AirDrop, which requires that Bluetooth be turned on for both devices, but does not require them to be paired. As Giulio stated, they are not designed to do that.

No iPhone can be connected to an iPad via BT (and viceversa).

Regards

Giulio

This should help: https://support.apple.com/en-gb/HT201205

sapper wrote:

This should help: https://support.apple.com/en-gb/HT201205

It's actually completely irrelevant. It applies only to accessories.

Sorry, no, Sapper. That’s not related to the OP’s question.

Regards

Giulio