Can somebody hack into my phone camera and spy on me i have and iPhone 6s and if they can hack into it can they retrieve audio how can I stop it?

Stop worrying ! The only way that could happen - is if someone could remotely access the operating system of your phone - and force it to turn on your camera and audio. In order to do that - they would have to be able to decode the security 'handshake' connection your handset has with the mobile network. To date - no-one has been able to do that !