How do I turn on the peak performance

Hi kalu132,

We appreciate you reaching out to us. We understand that you are looking to turn on peak performance.

It looks like you are referring to your device's battery to deliver peak performance.

If that is correct, please look into your battery service options here: Batteries - Service and Recycling - Apple

All rechargeable batteries are consumable components that become less effective as they chemically age.

That being said, it is expected that your device's battery will degrade, and it won't be able to deliver peak performance.

You can use the article below as a reference.

iPhone Battery and Performance - Apple Support

Take care!