How do I disable one-tap fuelling?

Is the one-tap fuelling feature automatically enabled?

Is one-tap fuelling available for both iOS and Android devices?

Do I need to enable any presets or settings to enable the One-tap feature?

How do I set up my one-tap fuelling preferences?

Can I disable one-tap fuelling after I try it out?

I refuelled lesser than my preset amount, how much will I be charged?