Need to accept credit cards in a React Native application? react-native-square-pos is a great solution.
Square is a well-known solution for accepting credit cards via a mobile app. Their famous Square Reader inserts into Android or iOS phones via the headphone jack or the Lightning port, allowing users to either swipe or tap credit cards.
If your app is based in the United States you can likely use the Square In-App Payments SDK for a smoother user experience. Unfortunately, if you're not in the U.S. you're out of luck.
The solution for non-American residents is Square Point-of-Sale, a standalone application for Android / iOS which allows you to accept credit cards.