1. Open your BTC wallet. On the wallet homepage, tap “>” - “Sub-address Management”.
2. Find the child address whose private key you want to export and swipe left.
3. Enter your wallet password.
4. Follow the on-screen instructions to write down the full private key on paper and keep it safely.
5. Double-check that the private key is complete and accurate.
Note: The exported private key applies only to the selected child address and can only be used to restore that child address.