I have researched the above problem on line for my iPhone 12 and don't see an good solution or an App to prevent these calls. It's so easy to do to make the pocket call. Can't you devise a confirmation that the call is intentional? This is a recurring problem that Apple should take note of. I am a BIG Apple fan but this is more than an annoyance for someone who makes a living using the iPhone to call trusted business associates.
iPhone 12, 14
First I’ve heard of this sort of calling. I have seen some other possibly-related touch-screen issues, though. If you’re keeping your iPhone in a shirt pocket, keep the display away from your body and see if the dialing problem persists.
The brute-force solution is a case with a cover. I’ve purchased various cases from Burkley (now Blackbrook):
https://blackbrookcase.com/collections/leather-iphone-12-cases
and they offer iPhone cases with covers.
Send your product feedback to Apple, too: Product Feedback - Apple
You are not addressing Apple here. This is a user to user support forum and Apple does not participate here. If you are experiencing a problem like that, I suggest that you make a Genius Bar appointment to have the device checked. If you have locked the screen and are using Face ID, there is no way to make a phone call in your pocket. If it seems that your device does, then Apple would probably like to see it.
If you do not wish to have the phone examined, then you are welcome to provide feedback to Apple to ask them about fixing your issue, www.apple.com/feedback/iphone.html or you can use the Contact Support link at the top of the page here to speak directly with Apple Support.
Pocket or butt calls are more than just an annoyance
