Expo or create-react-native-app projects include react-native-vector-icons out of the box, so all you need to do is install react-native-elements
yarn add react-native-elements
or
npm install react-native-elements --save
Note:
If you see the UNMET PEER DEPENDENCY
warning for react-native-vector-icons like below, you can ignore it as react-native-vector-icons is already installed by expo or crna.