"8938" is a feature on the iPhone that automatically copies over a one-time verification code to your keyboard so you dont have to manually enter it. This feature is related to the 2-factor authentication codes that people receive via text message when they try to log into some websites. The feature is nicknamed "8938" because it refers to a specific iPhone screenshot showing a text code from messages (8938) thats red-circled. It is not a standalone app or feature, but rather a part of the iPhones messaging system. The feature has gained some attention on social media platforms like Twitter, where it has become the subject of a running joke.