1. install react-native-phone-call package using npm
$ npm install --save react-native-phone-call
2. create a method called makeCall()
makeCall = (number) => { const args = { number: number, // String value with the number to call prompt: true // Optional boolean property. Determines if the user should be prompt prior to the call } call(args).catch(console.error)}
3. call the method in onPress event of a TouchableOpacity
<TouchableOpacity key={index} style={{width: '80%', height: 80, backgroundColor: 'rgb(186, 186, 186)', alignItems:'center', justifyContent: 'space-between', borderBottomWidth: 0.5, borderBottomColor: '#000000'}} onPress={()=> this.makeCall(item.contactNumber)}>