If you prefer to perform the repair yourself or are looking for alternative parts: About genuine iPhone batteries - Apple Support
Use the Apple Locate tool to find certified repair centers near you that use genuine parts and follow Apple’s standards. where to buy a new iphone battery
For experienced users, Apple’s Self Service Repair store sells genuine parts and tools for specific iPhone models (iPhone 12 and later). DIY & Third-Party Retailers If you prefer to perform the repair yourself