You can choose to store the backed up apps in the internal storage or memory card or in the USB.
A single tap on the app’s name will backup the app. The three dots against each app name will diplay the option to share the app and see its info in the settings. It also has the feature of auto backup.
It offers a bit more features including running the app, seeing its info, sharing it and uninstalling it.
2. Long press the app you want to backup and click on backup button.
3. The app will be backed up in the default location of Internal Storage/backups/apps unless you have changed it.