How to know if my battery is original or fake

transmara wrote:

Only Apple Store locations and Apple Authorized Service Providers have access to the genuine iPhone battery components. For more information: About genuine iPhone batteries - Apple Support

It's new and somewhat limited, but the Self-Repair store is now online. But the battery is now available for the iPhone 13 Pro Max. It doesn't seem that cheap, but there is the part return credit for sending in the replaced part.

https://selfservicerepair.com/home

This is the battery, replacement adhesive, screws, and security screws:

Only Apple Store locations and Apple Authorized Service Providers have access to the genuine iPhone battery components. For more information: About genuine iPhone batteries - Apple Support

If you had it replaced at an Apple Store or Apple authorized service center then it is a genuine battery.

How to know if my battery had been replaced