my iphone 6 64gb not working wifi and bluetooth how to repair?

first try forced restart...

iPhone 6

1. Press and hold both the Sleep/Wake button and the Home button.
2. When the Apple logo appears, release both buttons.

When it starts again do...

Settings, General, Reset, Reset network settings.

If it still bad get it repaired. It may cost more than a new phone though

Hi!

Check that: iPhone Repair - Official Apple Support