Apple's New iOS Feature Could Warn You of Repair Shop Scams - Gizmodo
If your iPhone repair was done using OEM parts then “Genuine Apple Part” will be listed.
Via the Self Service Repair program, Apple will let customers make DIY repairs by selling them genuine parts and providing installation instructions.
While Apple recommends customers go through its professional repair channels (Apple, an Apple Authorized Service Providers, or an Independent Repair Providers), anyone who wants to make their own repairs can do so with genuine Apple parts shipped directly from the source.