If you have an iPhone 12 or iPhone 12 Pro and it's having difficulty with calls — specifically, the earpiece isn't working so you can't hear the person you're talking to — you're not alone. In fact, Apple just launched a service program that will fix the problem. And it'll do it for free.
According to Apple, the sound issue is caused by "a component that might fail on the receiver module" and it only is affecting iPhone 12 and iPhone 12 Pro models that were manufactured between October 2020 and April 2021. It apparently has not been affecting iPhone 12 mini and iPhone 12 Pro Max models, so if you're having earpiece issues with those iPhones, the service program will not fix them.
If you have an iPhone 12 or iPhone 12 Pro that's experiencing these issues, you have three options. You can take it to an Apple Authorized Service Provider. You can take it to an Apple Retail Store (but be sure to make an appointment first). Or you can connect Apple Support and use its mail-in service (Apple will mail you the shipping box) in case you don't want to leave the house.
The service program will not fix other issues you have with your iPhone 12 or iPhone 12 Pro, such as a cracked screen. In fact, if your iPhone has issues that prevent Apple's ability to fix the earpiece issue, you'll need to get those fixed beforehand.