If your ZenFone device is preloaded with ASUS Data Transfer, you can launch it from the Settings menu:
ZC600KL: Settings > Backup & Reset > Data Transfer
For devices with Android O or later: Settings > System > Data Transfer
You can also do a “Data Transfer” keyword search in the Settings menu and find Data Transfer under the System menu.
However, if your device is not preloaded with Data Transfer, you can go to Google Play and search the keyword “ASUS Data Transfer,” or tap the download link of Google Play:
Download and install ASUS Data Transfer, then launch it from the app drawer.